Ewa Marine is the only option if you want the bag style housing. But what kind of SLR do yu use? If it uses 35mm film then you may be able to track down a used housing. People are tradding film for digital and the housing for film camera are getting very hard to sell. You see them posted here for 1/5th of what they sold for new. My 35mm Nikons have very little resale value anymore as "everyone is selling off the F5, N90s and so on. If you have a common 35mm SLR just wait or post a few "WTB" ads. for the housing.
About the housing costing more than the camera. That's typical. I just bought a $1,400 housing. The advice many peole give is to select a housing first then buy a camera to put it it.