Single blade sabers are a bit less than the double-ended ones. They average about $20.
The double-ended only light up on ONE end. And they are enormous.
If you're getting them for a kid, I can't recommend it for a kid under 6. Actually probably older, just b/c they are enormous (even the single blade ones) and heavy and have no belt-clips!
Enormous, heavy, and no way to clip it onto him was how my son ended up having his stolen. OK so he/we lost it, but it wasn't there when we went back for it and never made it to lost and found, which means someone took it. He had handed it to one of us or put it on a bench, and it was so new we didn't think of it and "just like that, it's gone". It was his birthday present, too.
(Once we realized that we had a hand in the loss, that it wasn't just him being careless, we felt so guilty we bought him two $10 light sabers, which are light (no batteries for sound or lights) and have a belt clip.)
Oh, and you can't really see the color/light in the daytime, it's too weak. (honestly I wasn't impressed even before it was lost!)
And at DLR you don't get a pin like they say you do at WDW. They do include batteries, though!