Initially I bought 10m each of 43 and 75micron laminate from www.aussieflight.com.au for $1/m. That amount covered Le Fish fuselage three times, the wing twice, and the wing of my next ultra light build.If you want larger quantities you can buy full rolls from a laminating supplies business. It works out much cheaper per metre.
I bought two GBC EZload laminate rolls
Updated GBC link (Thanks Lex_Dysia)
1.7mil (42.5micron) x 305mm x 100m
3mil (75micron) x 305mm x 60m
Price was $45/roll plus freight and GST and it's perfect. Goes on easily with a warm clothes iron (Wool setting) and it will cover many future planes.