I looked into getting some miniture pigs last year or so. Because of foot and mouth there are a lot of regulations though. When I looked you had to have a concreated area as well as grassy for the pig. Also, if you wanted to take it for a walk a vet would have to check the route first and I iirc give you a certificate if it was acceptable. Obviously a private vet doing that would cost heaps! I believ there are a lot of expensive vacinations pigs need on a regular basis too?
Maifa, not being rude but I believe the OP was asking about pets, like a cat, I don't think they want one to rear and kill!