Just two hours away from Mayan Beach Garden lies the Belizean free zone. This Duty-free zone has over a kilometer of inexpensive imports from China and India at very inexpensive prices. You can find clothing, tires, some house hold goods, and a lot of dollar store items. In addition, there are two casinos, and soon to be hotel.
In order to enter the free zone from Chetumal, you must stop at the little immigration hut to show your passport and visa. You visa is the tourist card that you received as you entered Mexico. Without this card, you will not be allowed into the free zone. Just show it to them and make sure you have it again to return. You will not officially be leaving Mexico or entering Belize, but let them know that you are going to the free zone or "Zone Libre". They will pass you on. The Free Zone is just across the River Hondo. Follow the chain link fence to your left. There is a 10 pesos fee for entering the Free Zone.
Once inside, you may pay with dollars or pesos. Some stores will be priced in both pesos and dollars, making shopping confusing. Make sure and ask what the denomination is if it seems too cheap or two expensive. Items are seldom priced in Belizean dollars.
When you leave the free zone, you will be faced with two options - things to declare or not to declare. You will also have to press a button for the green light/red light search like they do as you enter Mexico on a flight. There are limits to what you can purchase. They are looking for obvious purchases for items to sell in stores and also liquor. Ask at the store what the limits are. The sales people speak English and are usually knowledgeable about the laws, especially the liquor stores. Liquor can be 1/2 the price you might see in the US.