I own a scuba tank and bought it thinking that I could easily fill my own HPA tank. However, I have now figured out(after filling the HPA tank only once) that the scuba needs a compressor? Is this right? Please help! If I need to buy a compressor is there anything out there that is cheap? I really dont want the field version kind and I dont want to spend like $300+ to get one(Ionly spent $115 on the scuba tank.)Help!