My boys built their lightsabers last June at DTD at the Once Upon a Toy store. We just came back from Disney last week and they still had the display up at the Tatooine Traders shop as you exit the Star Tours ride.
They cost around $20 each for the single blade. You can pick which color you want it to light up (you put a colored disc inside the handle) and it does make noise. Be warned that they are not very easy to put together. They have pictured instructions on the display, but they seemed to have left out a few steps. We asked for help from a CM for ours. Here is a picture of the display and the lightsabers my boys built. My youngest does not have the handle extended so you can see how long it is (so you know how much room you need in your suitcase to take it home)