Even the chocovision start at $400 us, so thats out.
For $20 you can go to Mall*Wart or the like and get a cheapo electric heating blanket. Set your bowl, or better, a 1/2 insert on this with the lowest setting. Melt your couverture in the nuker and pour into the insert. Temper using the "seeding method". Should hold temper for 45-60 mins.
@kuan.........I've used Mycryo in a pinch and it works OK, but honestly it doesn't really save that much time or hassle. Also, some years ago I bought one of those Chocovision "Revolation" tempering machines when I was but a noob. That didn't save much time either, and it only tempers 1 lb max at a time, and 1 lb of chocolate is basically nothing. Tempering really isn't that difficult once you're used to doing it. Holding temper and keeping the chocolate workable for longer periods of time is the tricky part. I make a "nest" out of an insulated cooler blanket and a heating pad and I stick my stainless steel bowl in it and it works pretty darn well.