Bad deal or not?

I'm selling 4 GC 250 PSI 1/2" electric valves, 4 Firestone 3/8" 2600 bags, 1 5 gallon 8 1/2" port tank, 1 single and one dual white face 200 PSI gauges, 100' dot 1/2" airline, 30' 1/4" airline, 2 switches, front cups for 88-98 chevy/gmc, Viair 380 compressor, pressure switch, and all fitings for 600 bucks to a guy I know. Am I getting screwed or is this a fair price for somehting that has been sitting in my closet collecting dust for 6 months now? I bought all the stuff from Jason @ suicidedoors.com. Thanks alot for any replies.