OK - I just went through my Jag stuff -
I have an extra Tempest 2000, boxed, with instructions. The box looks like hell, but that's how I got it, pre-owned at EB, sometime in '97. The cart looks fine, including the label. Based on your original post, though, I assume you don't care as long as it works. It does.
I also have an extra Doom, and an extra Battlesphere
, but I'm keeping them in case I ever have a chance to play the Jag networked with anyone. It's not likely, but it's nice to dream.
If you want the Tempest 2k, though, it's got your name on it. DP Advance says $15. Ebay says about $10. Somewhere around those sounds fair.
I don't suppose you have either Dreamcast Gauntlet or Dreamcast Spiderman, that you'd want to trade, huh?