Highly doubt you can rent exotic cars in Hungry or Czech for cheap.
Rental car companies won't even let you take their mid range cars to those countries and the roads aren't really that great. I'd save that money to do it in North America.
Here's a link though:
https://europeluxurycars.com/rent-lu...rs-cars-rental
Also if you do end up doing it, I'd try my hardest to avoid renting one in the city. People do not give a shit about their cars in Europe. Nicks and Scuffs are pretty much standard daily affair since the roads are so narrow and busy. We road tripped across Europe in a van and driving in the city was seriously annoying. I'd imagine a lambo would be 10 times more anxiety-inducing.