Why YSK is because this is where my ultra detailed intuitive perspective shines and I can tell you how to generate revenue on demand using eBay the old school way that still works.
This was a reply to someone a few days ago about how to sell a large gaming collection. That post was deleted, but this info was popular, so here it is as a post that will stay up.
I ran high end bicycle consignment on eBay professionally. It was a side thing when I was a Buyer for a bike shop chain, and what I did part time for nearly 2 years after disability. In total I sold $139k on that account.
You must be established on eBay in the first place. You need an account with at least 60-100 feedback first. Make purchases to get some of that, sell a few low value (to you) items at a really good deal for others and across different categories. You're trying to show that you are a real person and imply your country of origin. Ship everything you sell the same day that payment clears, and get a receipt from the logistics handler every time.
When you package any item, take a picture of the item in the box, and keep a scale on your packaging table to take a picture of the boxed item with the weight on camera after sealing the box. You are going to have 5-10% of customers that are scammers. This combo will save you from their scams. You can use the imaged weight and shipping weight from the logistics carrier receipt to dispute the photo of empty packaging scam.
Shipping insurance is a complete waste of money. The most expensive thing I sold was a $14,900 Felt IA FRD without the Zipp wheels for $9600 on eBay after 1 season of use. That was a major outlier. Most bikes were $1k-$3k, but I was dealing with some pricey stuff that represented substantial risk. I had to deal with major issues a few times despite using better shipping practices than anyone else I have ever encountered. If you own the merch, you own the risk. I didn't have that luxury. I developed the strategy of finding the advertised cost of the cheapest insurance option I had available and I paid this amount of the sale into my insurance account separately. That account went negative once near the beginning, but stayed about even with incidental drains occasionally. The hassle and time it takes to go in circles with the third party shipping insurance companies is the intentional obfuscation built into their scam. You will be able to recover any lost amount simply by working a minimum wage job for the same amount of time it will take you to get money out of these scammers. You could probably panhandle the amount quicker than the amount of time you will spend trying to get them to pay.
It will be nearly impossible for you to keep track of all of the fees and costs of eBay. I tracked everything as fees; taxes, logistics, insurance, supplies, everything. In could not close monthly books until 3-4 months after the sale. The total cost to actually sell items was 39% of the total sale as of April of 2017 with an account in perfect standing ~98% of the time. The lowest I ever got was 37% in a month and never topped 40%.
When you post items, have them boxed in advance and post the last picture of the item boxed. Add a unique number to this box, have it in the picture, and add it in the description of the item so that you know what is in each box to match with the purchase. Don't count on your descriptions or listing. Don't package whatever sold in the last few days after the listing is ended. You WILL screw this up and send the wrong things to the wrong people or forget something no matter how diligent you try to be. It is much better to have a label that prints and includes the listing details with the unique number matching the box; like today I sold: "K4R3N," "IAN123," and "JK1337," and must match these values to boxes that say the same. Like, if you are selling video games, do not do: Brombus Brzezinski bought Final Fantasy VII Special Edition (6/10), Bambi Blowater bought Final Fantasy VIII Special Remastered Edition (7/10), and Blumbus Bluewaters bought Final Fantasy VII (7/10). If you package what sells after the fact, you'll be slow and when problems with logistics happen your delay is only going to make the problems much worse. It does not matter that you have x days to ship items in the system or described in your listing. Ship it the same day that payment clears as a point of pride. When you have real problems, that is the only time to use your shipping window. This is the only way you can keep an account in prefect shape long term.
The price others list items at is a joke. Ignore this nonsense and only look at the sold history for items in the last 60 days. If you can provide better information and images than anyone else in this sold history, you are likely worth 10-15% more than the rest. Keeping a listing up costs money and is a loss that must be accounted for.
Low demand items without substantial sold history are worth less in this market. Emotional attachment is worthless, sold history is everything.
This is the key to doing well with generating revenue on demand: eBay has the most traffic of customers willing to make purchases on Sunday evenings between 9-11pm Eastern time as this will bridge the entire continental USA so that it is 5-8pm in California. The trick is to list your items with ten day auctions and time your listings so that they end in this time window on Sunday. In other words, you schedule ten day auctions that start Thursday evening in this time slot. Stagger your listings around 10-15 minutes apart so that a person can bid on and watch multiple items. Now, this is where the real hack happens and the details matter. You list these items to start for $0.99 with free shipping if possible, and with no reserve. This is not optional. Your conservative fear and desire to list the starting price higher will kill traffic interest and volume of initial views. The item must have an active sold history for this to work. An active sold history means there is demand. The initial traffic of a real no reserve auction on eBay will max out your visibility priority for suggested and relevant cross posts. This is more powerful of a tool than any other form of promotion. You're going to get a several messages from all the crazy stupid people that want you to take their special offer of $2 to end the item. You love this stupidity because these idiots flock to this kind of fantasy listing in droves and are the reason this trick is so effective in the first place. Be nice to them and they'll view the listing hundreds of times. A few might even go crazy with a sub $5 bidding war, which is even better for the listing visibility. I did this with $1k-$4k bikes all the time. I almost always set the max sold history value for similar items, but I also did detailed listings unlike anyone has ever done before or since with high end bikes on eBay. I documented every scratch, bearing, and part, along with detailed wear descriptions where I was downright negative by typical salesperson standards. I also used my automotive painting background to photograph cosmetic issues before and after I did minor touchups and fixes to really high end stuff. You must think like a skeptical buyer that is afraid of getting scammed when you're creating listings and reassure them in a way that would satisfy yourself. Like prove that your games actually work in pictures, etc. There is only a minor element of sales pitch to tell what the item is and its intended use. The majority of your listing should be about telling the informed buyer every detail they are not even aware of questioning and gives them confidence to take the listing serious.
Only start your no reserve auctions to end on a Sunday that follows the 15th of the month, and only when there is not a holiday or major sporting event in the USA. People pay rent/mortgages on the 1st of the month. The largest pool of people with excess funds to spend a little more or get carried away with bidding are the people on the Sunday after the 15th of any given month. Never list items that are competing with themselves in auctions that are ending on the same night. Make your listings Buy it Now for a good price in the interm then convert these to no reserve auctions when you're ready. Avoid giving any excuses that might indicate the person can procrastinate and get the same thing later or for a better price like mentioning you have more of these, or even listing the same item in another listing with Buy it Now while an auction runs.
Overall, this is how you dominate eBay and get your stuff in front of the most people, most often, and that is how you make sales conversions. No matter what you do, you're going to have overburden that will not sell in any single market. This is why I was the Buyer for a bike shop chain that ran eBay and did swap meets too. Pick a number and and strategy for handling this. Like when you have sold $xx,xxx amount you're giving the rest away to N and quitting. You will never experience a day when the last item sells.
Last thing I didn't mention before, if eBay still has 1:1 images in the primary scrolling feed, absolutely make sure to photograph your leading image to make it as large as possible and fill the entire frame. Use a white infinite background or a low light studio photography setup. The background needs to be either 0x00 white or 0xff black, and the item itself needs to look real like it is not a stock photography image. The other images should be professional looking, but can be more flawed. The lead image should be edited using gimp with filters for contrast and saturation to make the thing pretty.