To date mine have run the gamut of anywhere from $80-$250. I have made lap, crib, twin, queen, etc. and I buy my fabrics almost exclusively from quilt shops (either online or locally). I try to only by when the fabrics are on sale. I buy my batting at Joanns when it is 40-50% off. And I buy thread almost every time I shop to keep stocked up on it (providing it's on sale).
I guess the key words here are sale, % off and sale! :-D