Any Suzuki dealer can get the kick start kit in for you - it's part number 26300-29813
That said, when I checked with Fowlers a couple of months ago it was £246.52 +VAT (£290 ish inc VAT).
I got a second hand set from a kicker model off ebay for £150, the kick start lever itself is a bit tired (slack in the swivel and deep gouges where it hits the footpeg) but the internals were all unmarked, it worked first kick and is fine as a back up. If I have time/can be bothered I may make up a bush to repair the swivel. In fairness I did have to buy it a new oil seal (generic seal of the right size from simplybearings.co.uk for about £2 delivered) and a new crankcase cover gasket (£13 from Suzuki) both of which are obviously in the Suzuki kit but not reusable with second hand bits.
As mine's a bit slack, I did ask, and apparently the lever itself is about £130 from Suzuki, even without all the internals...
'02 Africa Twin (sold), GSX-R 1000 K5 (sold), '97 TL1000S, '08 DRZ400 SM/S, '92 CRM250