For a mere $5,000, buy it now, you can get an authentic, used in the show, vibrating Tribble, for sale now on eBay, complete with a certificate of authenticity from Chris Doohan, son of the actor who played Scotty.
This little fuzzball looks a wee bit worse for wear, but supposedly, it still jiggles. With two AA batteries, it can wiggle its way into your heart. Who knows — start with one and you could end up with a complete collection. You know, that's the trouble with Tribbles.