higher-end digital camera is in the $4,000 price range.  In other words, the actual total cost can actually double!

There is, however, an alternative approach:  buy a housing first, and then find the camera that fits it. While this may seem like putting the cart before the horse, it makes perfect financial sense --I've done it twice with great success.

Retailers will often discount discontinued housings and accessories enormously.  When that occurs, it's merely a matter of shopping to find a good deal on the matching camera. 

If the housing is discontinued, it's a good bet that so is the camera. In fact, it's probably what prompted the manufacturer to stop producing the housing. That doesn't necessarily mean that you have to shop for used equipment.  Giant online camera retailers, like  Adorama, B & H Video, or 47th Street Photo, carry back stocks of discontinued items at a reduced price.  Surprisingly, Amazon is also a good site to shop for camera equipment.  Ebay is another site for finding great deals on underwater equipment.

It may seem odd to buy a different brand camera system when you already own an existing one, but if the difference amounts to a savings of thousands of dollars the decision is an easy one.