So far, I haven't seen sims autonomously purchase things at the registers other than the food register. The general store register opens up an empty shopping list. Nothing is in it. But, if you use "buydebug" cheat in buy mode at home, you CAN buy tents, scooters, shower in a can, and many many more.
I placed a regular bookshop in my France neighborhood and the only books I could buy from it were from France (wine making, frog fishing scrolls, etc.) Maybe the shopping lists are specific to whatever region you're in? So, the list doesn't come up because there's no general store associated with the main hood? Of course, as you mentioned, you can always use buyDebug to get what you need. It's definitely not the same as your sim purchasing it for themselves, but it's all we got until (or unless) they make an OFB-type EP.