I read the sticky, and hope I am not being redundant.

My question is what might be the full cost for a student attending a university like Prince of Songhla, and when I say full cost I mean:

tuition

books

food

room for a (Thai national) student who is not working and only studying full time, approximations are fine.

Thanks in advance

You're asking a very vague question. It's like asking how much does a car cost or how much money do I need to travel. If there was only one car and one destination it would be easy. Just like the car and travel, there is more than one university in Thailand.

It shouldn't be too difficult for you to find the course fees for the course at the university in question plus what accommodation is available. Allowance for food and living costs is a variable you can work out. PS re books, if you want to make an assessment as to whether the uni is any good, one check is to visit the library facilities and also any bookshops in the area. It will tell you a lot if you know where to look. Also whether the uni is plugged into any online international access. This area a big giveaway.