Do they have walkers?

Yes, usually on aisle 3. My mom bought one for my aunt some months back. But look on every aisle.

I've seen a couple for sale

I saw one in the main aisle straight ahead on the left after the leather shop.

I've seen wheelchairs. I'm pretty sure they're for rent but I've not personally checked on price. Carts i have not seen.

They have wheelchairs that can be rented and they have grocery carts that can be rented not sure what they charge for the wheelchair rental it's really cheap but I do know that for the grocery carts you put down a $5 deposit and when you return it you get $3 back

For personal use while you're there or to purchase?

Yes

Used walkers are sometimes found here. Usually on the isle closest to the interstate.

Im pretty sure I saw some.for sale.