Prices around here were from $55-$129 for the flush only (no dropping the pan and not filter change)
I paid $85 for the flush because they used 10 quarts of 100% synthetic Mecron-V fluid. The Sport Trac requires Mercon-V which from the factory is a semi-synthetic. Some places will quote a lower price for regular fluid flushes, but when they find out the Sport Trac requires Mercon-V, the price can be a little higher. Others just charge $100 or more and include the higher fluid cost in the price for everybody.
Some places will charge more because they want to include an additive to clean out the transmission. That is an expensive additive that is not required, nor recommended as long as you have been changing/flushing your fluid on a regular basis.
...Rich