It does seem that different areas of the US and Canada have different allowable shop times. Mine are always 4 PM to 8PM on weekdays and 12 PM to 6 PM on weekends. You can buy pretty much anything except gift cards. Although, at our store you can't buy cigarettes at a regular check lane -- which is in the rules as a requirement -- but I've gotten beer many times.
Our store has mix&match build your own 6-packs that are nice. I often get papertowels, cat food, kitty litter, feminine products, beer, floss, packaging tape, envelopes, thumbtacks, & basically anything on my list that I need. My store sells stamps so sometimes I get a book of stamps if I'm running low or there aren't any hazmats. I pick out the cheapest 1/4 lb item I can spot, then I'll make my way over and get a single banana (usually $0.12 to $0.16) and then my third item. Or, I'll buy up a bunch of small items I need. It varies but you can buy pretty much anything the location sells. I might grab a $1.49 cheese, $0.12 banana, and then spend my other $10.39 on litter, or whatever. These shops can work out really well for you. Oh, and you can use coupons, freebie Friday card rewards, your store card to earn fuel points, and digital coupons so long as you make that total at the end. (Donating for the $1 charity causes doesn't count though as an item so be sure you get 3 items and spend $12 or get 30 items, etc. to add up to it).