dude, you should know the answer! DEPENDS ON WHAT YOU'RE PLANNING TO DO THERE! but to make you feel better, it'll be VERY cheap. food especially if you want to eat 'normal' thai meals it'll be around $2 USD for a meal, less if you decide to eat something quick and easy. hehehe tell me what you want to do first and i'll give you an estimated number.
this was what my brother spent in a week last time he was in thailand.
for a 5 day trip he spent less than $30 USD for food. and he said most of them were spent on snacks. haha
dude, seriously food is cheap. but if you're gonna go shopping, again it depends on where you go. there are the outside markets and then there are the malls. i suggest you go to the outside markets at night to avoid the heat and the high prices.
btw.. why are you asking? you gonna go to thailand? take me with you foo! i'll be your tour guide!