I think $150 is way too low, I'd do a minimum of $250-$300. I once saw the Eleanor Burns log cabin wreath at Keepsake Quilting,nicely done, but non-descript fabric and thewoman wanted $400, that's ridiculous for a quilt less than 36" square, maybe a queen at the very least for that price. However, most people don't want to pay what the quilt is worth just in fabric alone,they like Wal -Mart prices, but I don't think they have ever really compared the two, as there is no comparison. When I first started crafting in the "stone ages", the norm was 3 times the cost of materials, but a lot depends on the demographics. I'm sure this is clear as mud, but never price your quilts based on chain store quilts. Best of luck to your MIL on her craft store. You might also make lower priced items, like placemats and matching napkins, table runners, small wall hangings, etc.