You can order a new key for around $6. If you can't get a lock number or reference for the key, you might take a look at the key for another lock of the type that you have and then buy a key blank and file some ramps on it and make a bump key. The bump key will only work if the lock is a pin and cylinder type of lock. Take a look at lock bumping and you will see what I am talking about. By the way I think lock bumping is a nasty trick.