Just found a site with low-yardage minimums for prepreg. Don’t know the costs, but they are Hexcel’s prepregs and Boeing Cert
http://heatcon.com/aerospace-rotor-wing/material/prepregs/carbon-graphite
Found another one here in the UK I have not brought anything from them before tho
http://www.easycomposites.co.uk/products/carbon-fibre/pre-preg/vari-preg-22-twill-200g.aspx
£49 + Tax & Delivery, doesnt sound unreasonable for small amounts.