Wants to be driven to shop at 5 or 6 stores where she only spends $10 at each place instead of shopping for everything at one grocery. Saves 3 cents, not kidding, by stopping at additional places. Very feeble. Scared she's going to trip and fall and break a hip going in and out so many places. And takes 4 hours vs 1 hour of shopping.
Definitely set boundaries. And enforce them. Just be sure you are accomplishing what you intend. If you hire a companion/aide for an afternoon she probably won't care what they do together -- she is getting paid the same whether she is shopping or playing cards or looking at magazines with Auntie. If Auntie says, after a few weeks, I like Companion but I wish we could play more cards, you can explain, "Well it is up to you. Aide can only spend 4 hours with you once a week. If you could get your shopping done in two hours you'd have 2 hours to play cards." That situation has built-in boundaries. Four hours. That's it.
You can establish boundaries, too. "I have to leave by x o'clock today. If we rush through shopping a bit, we'd also have time to repot the houseplants you were telling me about."
Spending 4 hours to do something that could be done in 1 hour isn't reasonable. Going to multiple stores is the least efficient way of doing this task. But maybe, at her age, your dear aunt isn't particularly interested in reasonableness or efficiency. Maybe she enjoys spending time like this, and with you. She sees this as way more fun than watching television, and she has the bonus of "saving" a few pennies here and there. She can tell herself she is still a responsible homemaker.
Someday, perhaps, she won't even be able to go to one store, and you'll do her shopping for her, or help her shop online. That will be more efficient, but it will be kind of sad, too, don't you think? But until then decide how much time you are willing/able to spend with her and set your boundaries accordingly.
It wasn't like she met up with people she knew and visited in the aisles, she has lived here 17 years and made no effort to meet people. My mother on the other hand, chats with someone in every aisle, but still only shops the aisles where she needs something and is out of the store in less than 1 hour.
You can set boundaries. If it is usually 4 stores, tell her to check the flyers for only two, because you can only take her to two stores that time. Next time make it the other two stores.
Yes, she may trip and fall, but generally a hip breaks, then the person falls, not the other way around. It seems counter intuitive, but that is far more common. So I am saying if her hip is at risk of breaking, it will happen no matter where she is, home, shopping or at church.