I use to keep a bolt of off color white on white as well as a bolt different kinds of white on white. Believe me they went rapidly because I like biggg quilts. Also had a bolt of dark navy with all over gold flakes. Used that one bolt for background in making my super kingsize Christmas tree quilt. It is my Blue Ribbon Winner, Best of Show quilt, then another of the same quilt for my DD and my DGD.
All I want to emphasise is for you to get all you can bolt wise not neccessarily white because you will use it. Also bought a bolt of muslin which I never cared for but this one was a super grade, on sale, and the GM flower garden quilt was crying out for muslin. I like it so much I then made another GD garden done in many shades of purples for myself and using white lace over yellow for the center with lace trim around each flower garden block.
If any of you have a dealer license the quilt store in Batesville, Ar has beautiful fabrics. They wholesale and retail. I found out about them when I had my store and continue to go there as a regular customer. It is hard to go from wholesale purchasing to retail and pay double. I am just glad to be able to go at all.

If I can afford it (at that time) I buy the whole bolt or what is left on the bolt. I find that I use the tone on tone a lot.

If you find a tonal that you really like, buy a bunch of fabric. You'll use it somewhere.

I agree about buying the bolt if you can.

I would get 4 to 6 yards.

as much as you can afford

I buy black that way, too.

i love white on white and always pick some up when i have a 40% off coupon and cant find anythings else to use it on

My immediate thoughts--6-10 yards.