Ok, I'm going to rant. When we entered Belize five years ago, we sucked it up and paid duty on all our possessions. Even tho' we came in under the QRP (qualified retirement program) we wanted to expedite things. Since our goods were part of a larger container we paid our part and moved on. Belize has so few sources of income, they view expats as a rich well and draw as much as they can from it.
Two of our friends have just found that the customs well has just gotten more greedy. One person had several items shipped in with an invoice value of approximately $300 US. Customs reviewed the order and charged over $1400 BZ. Part of that was a fee of approx. $400 as a punishment for not purchasing in Belize. The fact that the items aren't produced or available in Belize had no bearing.
Another acquaintance bro't in a container of used furniture and an old truck. He'd paid $2,000 for the truck. Customs assessed a duty of $6,000 on the truck. He is being charged $12,000 duty on the shipment and $200/day storage at the port, even tho' the original agreement was to have the container bro't to San Ignacio accompanied by a Customs officer and opened here. We seem to have almost no control on anything, least of all our checkbooks. In an earlier discussion with a person in the Customs office, it was confirmed that there is an approved list of what charges should be, but it was admitted that we're at the whims of the particular officer on duty.
The inconsistencies seem to prove that "Gringo's" are only viewed as a source of income, both for the Customs agency and/or the officer himself.
My recommendation is to keep importation to a minimum and buy local furnishings.
Ir's also been suggested to me that you get a more reasonable treatment at the southern port of Big Creek.
Disclaimer - I have to admit that I didn't see the paperwork on the container brought in, but am going on what was described to me by another party.