Two thoughts on this
1) why is someone from Florida advertising on Pgh craigslist
2) if it is legit, does it have the part of the monorail that runs on the track?
You may want to print out the parts list for this set from bricklink and see if the important parts are there. Dan is our local expert on monorails, especially pricing, so it would be good to talk to him. I have no idea if this is a competitive price or whether the set is complete.