Back Lot Tours is a ride and walking tour. It does not cost anything, it is like any other attraction at WDW. It is a longer ride, at least 1/2 hour. I think it is worth checking out. Not our favorite but still wouldn't miss it.
The Backlot tour is included in the price of addmission to the Studios and takes about 45 minutes. There is a short pre-show before boarding the trams that take you through the backlot. Well worth it in my opinion. You can read all about it here: