There used to be LOTS of cars running on LPG here (propane) because it about halved the fuel bill (remember, we pay lots more for fuel than you guys). The price of gas has been rising since it was privatised until now, it is not much cheaper than petrol (when we say "gas", we mean "GAS", that's why the liquid fuel is called "petrol" - to avoid confusion.)
I have had several cars running on gas but the current one will be the last.
To get the best out of LPG, you need a higher compression ratio so the ultra low Model A CR won't allow you to burn much rubber
. Then there is the problem of where to put the tank. OK in say, a pickup but a roadster, coupe or sedan would be a challenge.