If you want to go all used( A good idea at 1st. ) you can pick up 5 line C kites pretty cheap now. I would suggest that with 3 lessons and used gear
you can get in around $1,200 U.S. dollars.
This could be WAY wrong for Great Britain though !!!!
So take your lessons, get connections and a feel for your area, THEN buy used proven quality kites.
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)