If you arrive in BKK in F with TG you should book a free TG limo into town and enjoy the style.
If you also leave BKK by TG F the return limo trip is on TG also.
As the other posts suggest go into town and enjoy.
If you really want to stay near the airport (still use the TG limos) I would recommend the Quality Suites Hotel with very big rooms a small swiming pool at less than 2.000 bahts a night.