I usually buy 1/2 yard pieces, this works great for scrappy quilts. This way I can have assorted pieces for a quilt. If I really lke it and its a fabric I may use in a couple quilts I buy 1 yard.
If I am buying for backing fabric I will buy 2 yards which will work for a crib/lap quilt. I wouldn't buy a lot at first being a beginner, you may change your mind what kind of quilts you want to make and the fabrics you like may change over time.
A lot depends on what kind of quilts you plan to make.
Baby? Children? Lap? Bedsize? :thumbup: