I pre-wash all fabrics so that the colors are set and there is no shrinking. I also do this to remove any chemicals from the fabric, which is important to the finished look of the items. I machine quilt all blankets and typically suggest backing them with a solid or small print in a coordinating color.
Pricing on any custom sewing may vary due to cost of materials. I will not buy cheap materials, as they end up producing cheap products no matter how good the workmanship is. However, I always to my best to get the cheapest price for the best quality available to help keep costs down.