Massages are available at every corner. Prices are in contrast to all other things in Thailand (as well as) not negotiable.
There are various massages – classical Thai massage is the cheapest (but also painful).
The oil massage is not really typical of Thailand and was introduced later for tourists.
It is like a light stroke with oil and is more relaxing than effective.
Massages cost depending on the type and duration between 300 and 800 TBH