Bangkok immigration announced you can now get a 1-month visa extension at local immigration in Thailand, the fee for this is 1900 Thai Baht. You can do this at any local immigration office in Thailand this was introduced on August 29 th 2014.Most tourist will get a visa on arrival in Thailand generally 30 days previously you could extend your stay for 7 days only so these new rules are good for tourists.
Can you extend a 30-day tourist visa in Thailand?
How many times can you extend a Thai tourist visa?