When I lived on PA you had to buy beer from a beer distributer. It was only sold in cases. If you wanted smaller qualities, like a 6 pack, you had to go to a bar.
Last year beer distributors were allowed to sell single 12 packs (you used to have to purchase two, no mix and match).
Taverns may sell up to two six packs to go.
Now many large grocery stores have beer cafes and can sell six packs or greater. Many have a “mix a six” option.