[PriernPayorse]

I agree with atalderic. To me, dual-pricing at cultural places like museums, old temples and ruins, are simply a form of subsidy, that allows Thai people to afford to visit, while simultaneously generating the needed revenue for things like maintenance, renovation etc. I am always mildly amused when people make such a big deal of this. I am by no means wealthy (probably one of the poorest Americans to ever visit Thailand, 555!), but I have never considered the price of admission to pose a financial hardship to me.
My question those who so principally oppose this policy is this: Should they raise the prices for Thais (possibly "pricing them out") or lower it for foreigners (possibly hurting quality of the place)?
As for paying too much in the markets... All I can say is learn to speak a little Thai, and get used to bargaining. Thai people can get ripped off too! Also, this happens everywhere in the world where prices are not clearly posted.

-mike