The only on-line BOM I have done was from the Fat Quarter Shop. It was a mystery designer, year long BOM. They only charged $10/month, including the shipping. It happened to be fabric I liked a lot, and the idea of a different designer making the block each month intrigued me. The shop also gave generous amounts of the fabric with every shipment, to allow for mis-cutting. Unless the fabric is the hard to find, unusual kind, I think it might be just too much to invest in one quilt.