feifei,
ALOT of ppl i know gets it confused with the Marche style foodcourt! the Marche style one is on 5th floor, but the one that is MUCH cheaper and with MUCH nicer food is one more floor up, on 6th floor. it is also very crowded, with alot of locals & tourists eating there! they use the coupon style of payment, ie. you go buy coupons 1st, then you pay with your food using the coupons, then after you finish eating, if you have extra coupons they have a seperate counter for you to return the unused coupons and get refund back.
everytime hubby and i eat there we will change about 200baht worth of coupons, then surely will have extra, then we return back lor.