Well the ad says it 2-4 oz fiberglass mat..

As far as worth, if your working with polyester resin and will also be using
woven roving with it, it might be worth something.

I purchased misc. rolls of both glass mat, roving and biaxle stuff for a
flat $1 /lb.. Ask the seller how much the whole roll weighs..

One thing you better be careful of.. make sure it hasn't been wet. If it has
and even if it has been dried out. The water will have effected the siezing
and it won't desolve properly with the polyester resin.. Walk away from it
if it show any evidence of ever being wet. (will show water stain marks.)


--
My opinion and experience. FWIW

Steve
s/v Good Intentions