I bought several items while in Poipet Cambodia, the local sellers gave me the real Cambodian price, they did not try to drive up the price for the rich barang (barang is the Khmer word for a farang).
I got a big styrofoam bowl of Cambodian deserts (deserts in Cambodia are awesome) for 10 baht (33cents), the seller gave me a bigger bowl to balance out the 10 baht cost. Most Cambodians buy a smaller bowl worth for less money but when I only had a 10 baht coin the lady selling the desert used the bigger bowl to give me an honest deal, she could have easily given me the smaller bowl (I would have not known the difference) but she was honest with me, I paid more so got more.