always buy backgrounds especially if they are on sale.
2 yds backgrounds(black, biege off white, white, tan and etc)
Potential border fabrics 2to3 yds
Blenders (marbles, fabrics that read solid) 1 yard
Backing fabric 6-9 yards
Often times you can find fabrics that can interchange and make a quilt so buy enough to have enough even if it's a lap quilt
Buy FatQ's to build your stash and for scrappy quilts good way to build your stash w/ lots of color.