Yard sales can get very hectic and you certainly won't have time to measure out pieces during the sale if you price it by the yard. That will also give the impression that you will cut. No, don't price it by the yard. I would bundle it in clear zip lock bags price so much per bag, no substitutions, no taking something out of one bag and putting it with another. $1 per yard is more than fair so if you want you can fill the bags with 5 yards of fabric and price them at $5 per bag.
If you have blends and polys and all different stuff I would price it less than that. Really the only buyers you will get for fabric are quilters and crafters and most of us prefer cotton but if you have a mixed bag with 6 or 7 yards of fabric and not all is cotton it should still sell at only $5 per bag.