Foam board supplier?

looksee wrote:

You might find a picture framer willing to do it for you, but it would be expensive, I don't think its something that would be asked for usually. For what you will pay you could buy a cutting mat, a metal ruler and a scalpel (and lots of blades, foam board blunts them very quickly), and do it yourself.

Thanks. I wouldnt mind cutting it myself its the getting it in the first place that im clueless about. So i'll go find a picture framer so.
To be honest i only need it to block the light from an attic conversion window so any large piece will do really and i can cut it down from there.

looksee wrote:

I'm not quite sure what you are doing, but i don't think foam board would be the best solution to block a window (are you just blocking the light?). How are you going to fix it? I suspect you will find cardboard will warp fairly quickly. You can buy black-out curtain lining, would something based on that help?

Yeah its just to block the morning light. I already have black-out curtain lining on velcro surround but the adhesive deteriorates and doesnt last and the velcor peels off on its own accord. Ive tried thumb tacking the velcro on but eventually it yeilds.
With the foam i was thinking i could just wedge it in and out if it was cut like a tap plug?. ventilation is not a problem because of this or anything as the roof is actually open on the surrounds.