Ive recently returned to thaoland on a 30 day tourist visa,ive headr that going to singaphore and buying a 3 month renetry visa with 20,000 baht would be the best way.Any help,Thanks

First we need to know what you have and what you want. By best I assume you mean to avoid the 90 day stay requirements.

Believe you are probably here on a 30 day visa exempt stamp that you obtained on entry into Thailand.

Believe you want to remain in Thailand for a period of more than 90 days. If not you can exit/return for another 30 day entry if that is what you have.

You could go to a consulate, such as in Singapore, and obtain a tourist visa that would allow 60+30 days stay in Thailand. This would cost about 1,000 baht but would require you have 20,000 baht with you if asked to show it.