It is good to know something about Thailand money before you visit Thailand. Thai currency is baht. One baht equals to 100 satang.
Let´s start with coins: They have 25 and 50-satang coins. These are very small and are basically useless. The other coins come in one, two, five and ten-Baht pieces.
Bills have different size and color according to denomination: 20-baht (green), 50-baht (blue), 100-baht (red), 500-baht (purple) and 1,000-baht (white). You will maybe find also a 10-baht bill, which is brown in color, but these bills are rarity.
Credit cards are generally accepted by major shops and hotels, but “hard cash” is preferred almost everywhere. If you have travelers checks, change them for cash at a bank exchange. These checks are only partly accepted outside of hotels. Bank exchange can be found in any tourist destination.
The ATM system in Thailand is not always the most reliable. Sometimes machines are down, this is true especially in the provinces. It makes sense to plan carefully your cash flow and to have some reserve in your pocket. Still, ATM debit cards or traveller’s cheques is the most popular way of bringing money to Thailand.