You really have 3 options when it comes to resin . . .
Poly about $30-35/gallon
VE about $45/gallon
Epoxy about $60/gallon
So, poly is the least expensive, not epoxy.
Epoxy is going to have much longer cure times, Poly will be about 15-20 minutes . . . I have found VE gives you about 45 minutes of working time.
USC is located in West Palm Beach, FL . . . not too far from you, but factor in shipping costs . . . maybe see if there is a local supplier.
6+ gallons of resin seems a bit high . . . I was thinking more around 4-5 gallons, but it depends on how much glass you are planning to use. There are fiberglass/resin calculators available online to check/verify what you will need.