What is the best visa option for a 6-month stay in Thailand: Education or Tourist visa?

Well, if you maximise a 60-days visa-exempt stay by the 30 days extension, you might be able to re-enter for a second exempt entry. However the 30-days extension on these second 60-days could be refused - it is always up to the discretion of the Immigration office. It's never guaranteed. Many reports indicate that Immigration offices are getting tougher on consecutive visa-exempt stays . . . . .and you need to ask your airline if they want a proof of onward travel out of Thailand within the first 60 days - as some airlines require this

Tourist visa/exemption x2, Low cost. Run u about 7-8k bht.

You can come on visa exempt free stamp for 60 days extend for 30 more 1900 baht then do a border bounce and spend a couple days in another country come back and re peat

If your passport allows, 60 day visa exempt plus a 30 day extension. Leave, come back and do it again.

With an ED Visa you have to attend classes with a TR Visa you are free to travel

Just get a multi-entry tourist visa before you come here.