I've actually done this! It worked out mostly well, though it's a perk reserved for us people at or over 25 years old :)

I used to do that until two rentals broke down, the second being quite scary and leaving me and my family stranded. Hertz and Sixt. Do you have a local rental place or something?

With my own car, I'm constantly keeping an eye for everything + regular maintenance.

  rent a nice large van!

Typically $100/day without mileage limits.