What i use:
Camera - $350
http://www.bhphotovideo.com/c/produc...al_Camera.html
Case - $230
http://www.bhphotovideo.com/c/produc..._Case_for.html
You may want to buy an extra O-ring at some point (after repeated use).. buy some silicone gel to coat the O-ring with after each use/clean
But total under $600.
You get a great Point and Shoot camera.. one of the best with manual controls yet small and easy to carry.
The case is also very solid.. dove to 100 ft no problems.
The reason i like the camera is i can shoot in RAW.. which is definitely needed unless you get some MEGA lights, your white balance is almost certainly off, so shooting RAW allows me to adjust in post process without quality loss.