I bought wood to make some modified Warre hives. (They are about an inch wider -- 14" outer dimensions, and shorter, and the top bars are more narrow.) I'd like to eventually make a lot of hives, because I'd like to make a living from beekeeping. I'm afraid I need to cut the fabric about 18"x18", though if I can cut it to say 15"x15", maybe I could finish more hives with less fabric.

I have a 15% off coupon from Hancock fabrics that I could use to buy 100% jute burlap 36" wide, $2.79 per yard. (I don't know the shipping.) It expires on the 10th, so I need to decide quickly. This means I could get 12 pieces of fabric and finish 6 hives per 3 yards. If I could cut 15"x15" I could get 7 hives per 3 yards.
That is $7.11+shipping and about $1.19 per hive.

The other option I have found is to use canvas painters drop cloth. I found one at lowes.com (again, not including shipping):
Blue Hawk 9-ft x 6-ft 8 Oz. Canvas Drop Cloth $10.98 This would be 12 hives at 18"x18" or 14 hives at 15"x15". That is $.92 per hive.

The drop cloth is cheaper, but I don't know if it is good enough.