Especially in the market, it is common for a foreigner to be duped with the prices of goods. One trick taught to us by a tour guide in Hongkong is to haggle the declared price at 50%. When the vendor says $10, you offer $5 and when the vendor cuts the price to $9 then you stick to the $5 until the vendor surrenders with the last price that would be something like $7 or maybe $8. But if you haggle with $8 at the outset, the vendor will stick with his price of $10. But in Bangkok, it is not the same because the prices in Bangkok can only be haggled slightly. For that example of $10 in Hongkong, you can only ask for $8 in Bangkok because haggling lower than 8 may be an insult to them.