I have a 6.5 inch DC kit with 5.5 inch pro comp rears, how much could I expect to get for them, if I decide to take it off... just looking at a ball park.

Ball park is a vague term. Depends on where you live and what the local (( Rich Kid )) population is. The Mall crawlers epidemic is the out right ruler of shit like that. Craigslist is a good place to start... Also hit up ebay.