Belize City. I can't remember but I think it is wednesdays that they hold market on the road that runs between the river and Holy Redeemer school. It is a main road but I would have to look up the name.
Nowadays you can make orders and even have custom furniture made through C's furniture world.
Of course you can also find the Mennonites and Mechonites up in their main settlements.
Depends what you need from them.