Can I extend my non-immigrant ED visa at Immigration instead of making a border run?

The user has a non-immigrant ED multiple entry visa for studying at Chulalongkorn University and is seeking options for extending their stay as their 90 days are expiring. They inquire about the possibility of extending their visa at Immigration rather than taking a border run due to budget constraints. Responses indicate that an extension can be obtained at Immigration for a fee of 1,900 THB, but it would require waiting for a whole day. Some users suggest that making a border run to Cambodia might be cheaper, but this option also incurs additional costs like the $30 visa fee and accommodation expenses.