[peter]

I want to buy about a dozen pieces of polystyrene foam board to tape to my
windows/doors/fireplace as temporary insulation for the season. Home stores
sell them: 1.5 inch x 2 feet x 4 feet for $4. This seems pretty expensive,
consider this is what most people throw out after unpacking a boxed product.
OK, the ones sold by home stores have an extra plastic sheet (vapor barrior)
and R-factors printed on them. I can live without these extras.

Where can I buy foam boards at lower price? I don't need the vapor barrior
or R factor.