Never pay up front unless you have to, and if you do, pay as little as possible. I stumped up a $500 deposit to visit a well-known school in Naples, only to find they'd been shut down when I got there.
They very quickly refunded the money, but I could have done without the aggro, and I can well imagine a less scrupulous operator pulling the shutters down, taking the phone off the hook & leaving students with a large hole in their bank account and no school.
Caveat emptor