I use Walmart for vehicles and the deep cycle in the RV. They're pretty good batteries, and I can get one nearly anywhere and likely 24 hours a day.
I'd been using Sam's Club batts but got tired of their access limitations. Unsat for the RV and vehicle situation, but the GP24 Marine Start batteries for the boat, have a little more capacity than the WM ones. It'll start on One and re-start on Both even if one is weak. And.. Sam's had $25 instant rebate on their flooded batteries right when I needed one. $39 for a new MS battery was sweet!
Shipmates, I'm glad this discussion is so practical! Sometimes More doesn't bring Better. A friend asked me to help with dead batts in is 26 Sundancer. Turned out they were AGM from WM, dead and WM said they wouldn't take a charge. They pro-rated the AGMs, furnished flooded and a partial refund of the much higher AGM price. My friend was very happy with the deal and his flooded batteries. BZ to WM on this one.