did you notice the width of the fabric? my lqs carries wide goods (108"-118") which range from $13.95 up to $18.95 a yard---which is reasonable-since you only need 3- 3 1/2 yds to back a quilt- could be the (shocking) price was on a wide fabric.
in the lqs's around here fabrics range from $7.95 on up to about $12.95- depending on the fabric-
you could join the (fabshophop) and visit over a hundred on line shops and find a vast range of prices-and selections. it pays to shop around- i spend about 1/2 of my quilting $$ at my lqs and the other 1/2 on line shopping....out of the on-line percentage- 85-90% is spent at fabric.com the other 10-15% is spent at random shops.