Wow, that is cheap! I've been getting glass from the local Home Depot in 16x20 sheets and cutting down. The 16x20 is $5 (plus tax of course) so less than $0.50 per 8x10 is fantastic.
i got the same deal from my local glass store in wheaton, il. so, you might want to check local businesses to see if they can provide the same deal.
gayle
If you order UV blocking glass and plan to coat wet plate negatives and print in any Alt process (albumen/salt/pt/pd/etc) you'll run into some issues with the whole "UV blocking" aspect of the glass.