I have got to the point where most times I see someone post that they want a certain chip, I dont even bother to look to see if I have one. Too many times I have spent an hour or more searching through traders, find the chip someone said they really wanted, and if the fair market value of the chip it $10, have them say they were looking for one cheap. Then offer half of the current value for it.
I think if you are posting a want list, put the price you would pay if it is in mint condition and the shipping. It can always be adjusted down if the condition is less than mint and you still want it.
I think if you do this, you will find a lot more of the chips you are looking for. usually someone on the board can come up with those ones you need.