Locally, Joanns, Hancocks, WalMart & Hobby Lobby all sell by the inch. Our WalMart & Hancocks have end of bolt sale bins. The only problem is that they don't always label these fabrics as to content.
Joanns almost always have their brand quilting cottons on sale for 30% off. If it was originally 8.99, 30% off is $6.30 per yard, $0.175 per inch. Not sure how they charge when it gets to rounding.
I love scrappy quilts & look forward to seeing yours.