I keep a list for used store purchases like a grocery shopping list. When someone outgrows a pair of shoes or pants, I write down that item on the list and the bigger size to start looking the next time I go thrift shopping. Look carefully for stains, rips, etc. Take the time to try clothes on and test electrical items. It can save you a lot of hassle trying to return items.
Many stores have strict or no return policies.
My favorite local store will let you return an item for in store credit only within 30 days with receipt and tag still attached to item. Watch for store specials, sales, and coupons. Ask the clerks, if you don't see any posted or advertised information. There's even a free weekly email newsletter. All rights reserved unless specifically noted.