I bought the lightsaber here. The lightsaber starts on blue and if you click the start up button again it changes color. If you shut it down and activate it again it defaults back to blue.
There's this set at amazon for 65 bucks, or 80 if you don't get to it in time for the deal. I have a similar set, and they're alright. They don't have smooth swing, and you'll have to change the blade color every time you turn it on, if you want something other than whatever the first color is. but for practicing twirling it might be what you're looking for.
Here’s a dual-set on Amazon for roughly the price of US cheapest hilt. Color-changing, sound, coupler.