A longer stay changes the math. Weekly and monthly rates lower the daily cost of training, and settling into one place makes the two-a-day rhythm easier to sustain.
Most camps sell monthly packages that cost less per day than single classes. Some bundle accommodation. Sumalee, Tiger Muay Thai and Santai all list longer options; confirm the current monthly rate and what it includes with the camp before you commit.
Check the current Thai visa rules with an official source for your nationality and length of stay. Rules change, and we do not give visa advice. Confirm accommodation for the full period, since monthly rooms book up in high season.
Compare verified camps, or prep with a US coach before you fly.