The Target Price is an alternative to the Maximum Price.
It is often used when you are the only offer on a listing.
For example if you sale Item A and there are many competitors you might want to have a Maximum Price of 19.99 which is accepted by buyers because there are other offers at or above this price. However when everyone sales out and you are the only one left on the listing you might want to sale it for 14.99. In this case you would have the Target Price at 14.99.