What is the typical cost for a 30-day visa extension in Thailand?

The quoted prices for a 30-day visa extension in Thailand vary significantly, with some agents on Soi Post Office charging between THB 4,500 and THB 5,500. However, many users in the comments suggest that the standard fee for a visa extension at the immigration office is only THB 1,900, which can be completed without an agent. They emphasize the simplicity of the process and recommend doing it oneself, highlighting that agents commonly charge higher rates for a task that can be accomplished independently. User experiences indicate that while some may choose to use agents for convenience, particularly in case of time constraints or complications, the general sentiment is to avoid them for such straightforward procedures.