I ended up buying 1/2" CDX for repairing my garage at ~$23 a sheet average because OSB was north of $30 and I had to drive an hour to get it.
If you buy stuff in batches, you can go to the service desk and get price adjustments at 14 days, just tell them you want it for store credit.
I once got an argument from an assistant manager and I told her I was happy to rebuy and return and I'd still get my $200, but they'd have to pay somebody to put the wood back. She said "are you going to do store credit" and I said "yeap, and I'll be using it toward another $1000 worth of stuff I'll see you in two weeks for". She caved.