I had this happen a few weeks ago. I agreed to sell an item for Xdollars, which was 125 less than my asking price. Then before I could get the item marked sold, I was offered $100 more than the accepted offer and he would cover shipping. Believe me, it was tempting, but i did not take the higher offer since I told the first guy yes. That being said, I have been the buyer and the guy tells me, paraphrased "wow, I priced this way too low. I have had X offers higher than yours, but you were first and we had a deal"...