Belize currency exchange is extremely easy for American visitors. The Belize dollar is locked at 2 BZ$ = 1 US$. So it’s very easy to see how much something is costing in US$ when you go shopping. Most accommodations and tours are listed in US$ prices, and most restaurants, shops, etc. are listed in BZ$. Nearly everyplace readily accepts US$ currency. Most also should accept traveler’s checks as long as you write your passport number or driver’s license number on the back.
Tipping is not usually included in restaurant charges. Typical is anywhere around 15% – similar to what you might tip in your country. Anything from 10-20% seems appropriate.