A few years back a group of US students were asked to think about the last 2 digits of their social security numbers and decide if they would pay that in dollars for any of a set of items in an auction. When the testers had the actual auction the students with higher numbers paid considerably more for the items on the average.
This is called anchoring. If you get someone thinking about a particular price then they are more likely to pay it or at least pay closer to what you want them to.