I was similar at the start of last year. Didn't bother renting a camera though. Just bought a cheap Bronica SQA with an 80mm and 50mm lens to try out MF photography

The camera didn't break the bank and I could have sold it later for near the same money. A year later and I am really enjoying MF photography so have decided to invest in MF now (have bought two other MF cameras in the last 2 months so be careful it can be addictive getting into this:-))

Up to you at the end of the day but I would recommend just getting your self a cheap Bronica or TLR or something to give it a go. Renting costs money and you only have the camera for a few days which I think means you don't get a proper feel for MF Photography

Best of luck