Yeah, I got mine up there too. Red box. Got an offer for $80 already maybe I should've taken it but I figured it's a popular but semi-rare title so maybe worth a little more?
I think your estimates are backwards - the hardcase version is the rarer more expensive 1st release version and the cardboard box release is not worth more than $50. If you have a $80 offer take it and run!
Comments
Realistically I think you could get $50 for the Hard Case version. $60 for the red box version.
You can always do like these folks do and set the bait and wait: You never know someone might bite.
http://cgi.ebay.com/Contra-Hard-Corps-Genesis-New-Sealed-Pristine-condition_W0QQitemZ350114364768QQcmdZViewItemQQptZVideo_Games_Games?hash=item5184713d60&_trksid=p3286.m20.l1116#ebayphotohosting
If you're already getting offers I'd probably just wait it out and see what offers come your way.