Around here, quilting is seen as a pastime for crafters, and not much value put on them as art. You may get a general idea by going to EBay and running a search. If you use the Advanced Search option, you can choose completed listings, giving you actual sales prices. Some very pretty things get no bids at all, or never sell because of unrealistic reserve prices. Also, those Chinese knockoffs are showing up as handmades, driving prices down further.
I have not had luck with consignment shops - their "cut" effectively reduces {to zero} the profit out of things I have brought in to sell that way. A shop that specializes inn country kitch may not be the place to sell an abstract piece. Small baby quilts may fly off shelves in a hospital gift shop, and languish in a gallery. You also need to figure your end user in when choosing colors and patterns. Cutesie juvenile prints make me gag, but may be perfect for baby showers.
As far as fairs go, they are fun, but be prepared to meet the quilt police for real. Read the judging criteria carefully, and take all the rules very literally.