Using this kite as an example from somebody with thousands of posts you may see that your 1st generation arc will not likely bring in $700.
http://www.powerkiteforum.com/viewthread.php?tid=29634
The Venom is a much sought after kite that is a few years newer and even at $400 this one has been for sale for a while.
Not trying to kill your sale but to explain why you are not seeing any interest. You may want to do a search on what S-arcs have sold for recently and
adjust your price?
Kites: 2.5m Profoil , Quadrifoil XL kitesurfer, NPW 5 Danger.
Flexifoil: 1.7m Sting, 4.9m Blade 3, 9m Blade 2.
Flysurfer : 19m Speed 2 SA, 7m Pulse
Peter Lynn :18m Phantom, 15m Synergy, 10m Synergy, 1200 Farc, 460 Sarc, 130 Tarc, 5m Peel, 4.2m , 6.4, 8.5 C-Quads, 3.5 LS2 single skin.
Rides: Flexi / P.L. Frankin'Buggy , Shaped + straight skiis, sand skis, Coyote blades. Core 95 ATB. RKB R2 ATB .
Ken (K2)