if you are booking online -- there should be reviews from previous tenants. you should look your favorites up on agoda.com (example) and see the ratings of others traveling on your budget. Enjoy Thailand -- we must all love it or we wouldn't be here.
plus if you are just changing a plane and do not leave the terminal you just walk from your arrival gate to your new departure gate. Usually you will have a duty free shopping area and some places to eat. I could be wrong but have never been anywhere a Debit/Credit card was not accepted for drinks/food. To be safe -- you can normally update your upcoming travel status on you bank's webpage. But that is becoming less and less required. Good luck -- have fun -- all us crusty bastards are just jealous you are traveling @ 19.