The prices are anywhere from $50-maybe $250 or so. Don't ever pay less than $150 on a Taurus. I paid 250 which is the highest I have heard of, but I love the guys work and it was my 4 vehicles done by him. The price varies by the quality of workmanship. In a Taurus for the film to be installed correctly, the window trim must be removed and then put back on after the car is tinted. For the rear window, if you don't want that ugly cut out line for the third brake light, parts will have to be removed and then replaced after the tint is installed. On my 2000 SEL my installer took out the entire rear deck, on the 2003 the third brake light simly lifts off. Film is relatively inexpesive and the price does not change much on different darknesses. Most film manufactures have several lines of quality. If you plan on keeping your car for a few more years always opt for at least a 5 year warrenty. Always choose a metalized film if you want to reflect the most heat and UVA/UVB rays.
Remember you are hiring an artist and you shouldn't be afraid to ask for an example of their work.