Please contact your bank and let them know you will be traveling in Thailand and may be using both debit and credit cards. If your bank doesn't know, they may block access to your card while you are here. On this note, there's no need to bring large quantities of cash. There are plenty of ATMs and we will make stops for you to take out money.
We suggest that each traveler allocate $100-200 for the entire trip. Most places only accept cash (Thai Baht)