Despite all the smiles, helpful hands, and generally genial disposition, Thais still expect to be paid for services rendered. Yeah OK, they really, really expect to be paid, service rendered fully or not.
I think that the simple solution is to use an ATM card to withdraw money in Thai Baht directly from your home savings account as you need it. I often carry around 5,000 THB in my wallet, which is far more than I would carry back in the US, but I do it for two reasons: it's very unlikely that you will be mugged and you use cash for just about everything here.
