The secret is not to buy your battery packs from Home Depot. The markup on those "genuine" Ryobi packs is insane, especially given they're just stuffed full of the same low quality 18650 cells as all the other Chinese garbage anyway.

I have a small fleet of Ryobi cordless stuff by now: A mower, a string trimmer, a blower, and one of those inflator thingies. I just buy the knockoff battery packs online for 1/3-1/4 of the cost and so far I've found the knockoffs to have just as much or more capacity and to be more reliable than the Ryobi branded ones. Home Depot wants $189 for a 40v, 4.0Ah pack. Or you can buy a "6.0Ah" knockoff which is probably actually still 4.0 online for $57. The price gulf on the 18v packs is even greater.