I have a used Pratt Hobbies Go Box for sale. It is in good condition except the alligator clips are showing signs of age (These are heavy duty clips I installed to replace the standard ones but these are now showing a little rust - can be cleaned or replaced easily). The unit works and comes with all original parts.
This is the version with the battery clips (not the car lighter plug).
Works great with low and mid power rockets. http://www.pratthobbies.com/proddetail.asp?prod=GO-12
25$ plus shipping