i would recommend if you go the 'yard sale' style sale- to advertise it as a 'quilt fabric sale' not as a yard sale- and perhaps mention in the add---something like many fabrics at $5 a yard (or what ever your intensions are-
i've been to a number of quilter's yard sales-and have picked up $5 bolts, and cut yard goods for $1 a yard---they wanted to get rid of the fabric-if you advertise a yard sale- people are looking for deals-figuring you are just (cleaning out) if that is not what you intend then you should make it pretty clear in your ad- possibly contact the local quilt guild and put an ad in their monthly newsletter-
if i went to a yard sale and saw cut fabric for $7-$8 a yard i would simply get back in my car and drive away- but if i went to a quilters sale that mentioned what to expect i may look at it differently- i certainly would not expect to pay what i would pay at the quilt shop though.