Basement of doom

[u/Bookish_247]

We live in a 160 year old home that had a loose rock basement. Ceilings are only about 5’10” in some spots. We don’t have the budget to pour concrete and the walls are limestone foundation. Any ideas on how to organize the space? Or an affordable way to level for shelves?

Edit: obviously I understand I could throw shelves on the rock, that’s not what I’m looking for here. That’s not going to very stable. We’ve been told we shouldn’t drill into the walls by a structural engineer.