Good news is that there is plenty of accomodation in low to moderate price range. And all places where I stayed have workable WiFi.

After my first few trips to Thailand I went through a phase where I would just look for a hotel when I showed up, but finally gave it up not due to lack of places but because I didn't want to go searching in the Asian heat.

I will make an additional comment on yoga. While retreats may cost more in N. America, you don't have to come to Thailand to partake. Heck, just got back from Peru, there were literally dozens of retreats there ...