IMHO Have you looked into the mainland, specifically Placencia? The place is like a coma...in a good way. There is a string of resorts from the tip of the peninsula, all the way up North th Maya Beach about 8-10 nmiles. { and more in Dandriga and Hopkins} if you really want cheap go there. Ther are some cheap places in Placencia, although most on Maya Beach are mid to high range. Dandriga and Hopkins can be very cheap--the the women's co-op in Hopkins. There are also Maya home stays where for a few dollars you get to use a Maya Shack and out houses. If you can do without the amenities than you really have a lot of choices. I guarentee there will be plenty to do in theses towns, with plenty of excursions to "pick off", with the exception of raucous nightlife. Last time We went, My wife & I stayed 1 week on Maya Beach where, like a diver, we decompressed. Then we did 3 nights in San Pedro,AC.
Go cheap for about two weeks, then on AC you could upgrade. This can be like a third world country, yet still has a pretty good safety net. Remember, the worst travel experiences make the best stories. Seriously, You could pull this off for $50-75 a day,including lodging[maybe $100] In SAn pedro you have to count on at least $50 in lodging alone. BTW book Rubies at least for a little while, you'll love it.
Here's my math. You can get a clean well-lighted place for $20us. ADD $20Us for each yes answer:
Do you Need[Stess NEED}
Indoor flush toilet{Yes for me:-}}
Private bath
Air conditioning
Pool
On sight bar
waterfront view
on site restaurant
My math may be a little fuzzy, and that's the way I like my vision also--blurry and ill-defined.
AmbergrisCaye.com 
