I have an upstairs bedroom that receives no to little heat/air. The first floor vents blow heat/air out with a lot of force, even when the vents are closed. Will an air duct blower fan help to at least make the upstairs room comfortable and generally how much would it cost to install one?

It may help your air situation but the best thing to do would be to call an installer and have them give you an estimate on the installation cost. Each home's configuration is different. It will involve an electrical connection of some sort as well. It all depends on where they suggest putting this unit. Have you ever had anyone inspect your vents for any kind of obstruction?