There are actually two Trends hotels on Caulker, the original Trends, which is a low-budget place not on the water, and Trends Beach Hotel which is a newer, nicer spot right at the main pier and next to the Sandbox restaurant. Regular rate there is about US$35 a night. That's for a double
The Spindrift has a variety of rooms, some quite inexpensive, especially off-season. So could probably stay at both these places for seven nights for a total of around US$300 double, or about $150 each for two people.
So, depending on what if anything else the package includes, and depending on what air fare you can find on your own, it may not be that great a deal.
Belize First magazine http://www.turq.com/belizefirst/