Go shopping at any of marine flea markets for your gear. If your looking for the "kit of death" just use the crack test. Pinch the BC fabric, if it cracks, it's good to go. Bend the hoses, if you see little cracks when it's bent over, make an offer. Metal parts should have either rust or vertigris, that green patina on the brass parts. The best part is the price, everything should be in the $5-$10 range . Converted tanks are rare but available. There are lots of spearguns, trigger mechanisms and safety locks need work. You can fully outfit yourself in your "kit of death" for less than $50.