Thailand is all about grabbing a plastic stool on a sticky Bangkok sidewalk for a plate of pad thai, then waking up early to see the temples before the heat sets in. You want to aim for the monsoon transition months when the weather breaks and the crowds thin out. It is the best time to see the country without fighting for space or blowing your whole savings on a hotel.
A typical trip runs around $2400 once you factor in flights, places to sleep, and all the mango sticky rice you can eat. When you are looking at a bill that size, you do not have to pay for the whole thing upfront if you use the right tools to manage your cash flow.
The 0% intro APR is a deadline, not free money, and any remaining balance at the end of the 15 months will start gathering standard interest.