Remove the tint yourself. It saves money, as well as saving the hassle when/if the shop destroys your rear defrost and says that it could not be helped. I know a lot of folks have different ideas on this, but I promise that this is the easiest method I've found.
Get a roll of cling wrap, or if you really want to stay on the cheap you can probably use plastic shopping bags. Use "Simple Green" cleaner, spray liberally on the rear window, then contain it on the window using the cling wrap. It is best to do this on a hot, sunny day if possible. Allow the window to sit in the sun for about half an hour. If it's cool out, you can also use a blow dryer or heat gun. Start at one corner, and slowly work it loose. Make sure that the adhesive is coming off with the tint...this is where most people make the mistake of yanking the film off and leaving the nasty adhesive. Keeping the adhesive and film together, slowly pull the tint off. If the film and adhesive start to separate, stop, hit it with a little more Simple Green, cover it again, and use the heat on it for a few minutes. This will make the tint come off clean, so you don't have to worry about destroying the rear defrost.
