yeah, its cheap for most, but when you have a work permit and a company setup so that you are operating legally within Thailand it can become expensive paying yearly company taxes and fees.
I have had Thai clients ask to see my work permit before and I am very proud to be able to show them it as most foreign freelancers dont have one.
couple of contracts a year paid in pounds/usd/euro/yen and you could sustain a happy life.
visas are a bastard, you need to skip the country every few months to renew your tourist visa.