That is not much of a deal.
My kit was $150 on ebay with a 90 day warranty from revolution cycles. I am sure you can work out a deal for 20 kits with someone.
This auction went for $121 total (local pick up so only $70 handling)
60cc MOTORIZED BICYCLE MOTOR SCOOTER BIKE ENGINE MOPED - eBay (item 310046846642 end time May-15-08 21:00:00 PDT)
Revolution cycle has 59 kits available,
66cc NTJL Motorized Bicycle Engine Kit 08-EPA Certified - eBay (item 320253306826 end time Jun-16-08 04:19:23 PDT)
make him an offer for 20 @ $120 and see what he says.