We normally stay at Ruby's:

Welcome To Ruby's Hotel, San Pedro, Ambergris Caye, Belize, Central America

It's not a tourist trap like many others. Nice, clean, and on the beach. I didn't find the place until my third trip there. $45 US/night. If I can't stay there, I don't go - some place I have trusted over the years.

You and one other person can get a day bone/tarpon fishing the flats for $200-$300. Fishing the reef is less than that. Anything else, let me know.