Snorkeling trip coming up...

[TCRedwing182]

I will be doing some snorkeling on a trip in a few months an am very interested in taking my camera down with me. I am trying to find a decent case for Nikon D300 (Ikelites and the such are out of my range) and was wondering if anyone has any suggestions. Also, being snorkeling and not diving, should I worry about finding a case that has room for an external or pop-up flash? Is light much of an issue at 5-10ft? Thanks!