I get most of the epoxy that I use from Fiberglass coatsing Inc...
http://www.fgci.com
Their 2:1 epoxy 3 gallon kit is about $100
Their 3:1, 4:1 and 5:1 epoxy 5 gallon kits are about $175
Its hard to beat those prices for epoxy resin. Their epoxy products are very good and boast extremely good physical properties when compared to others. The 4:1 and 5:1 epoxies, however, tend to have very short working times. But during this time of the year their working times are a little better.