Corrugatd plstic sheets

Am looking for some corrugated plastic sheeting to put on he roof and maybe sides f a walk in run w are having. does anyone know where to get some reasonably priced ones and what type do you recommend please?

Wickes were the cheapest when I bought them. They can catch the wind so you need to secure them carefully, with a guide hole so they don't crack and some kind of rubber thingy around the screw to stop water getting in.

Wickes: (8ft x 2ft)
http://www.wickes.co.uk/Wickes-PVCu-Clear-Corrugated-Sheet-660x2400mm/p/240152

B&Q: (6ft x 2ft) More expensive but might fit in a car
http://www.diy.com/departments/pvc-roofing-sheet-1800mm-x-660mm/35458_BQ.prd

Fixings:
http://www.wickes.co.uk/Wickes-Fixings-For-Corrugated-Sheets-Pack-100/p/164037

Thanks Tim, I will have a look at the links