That does work to a point, but be sure it is what you want extra of.
Personally, I like to build up with tone on tones. I find I always need those and never have enough of them. Also, Reds are a bugger to match so when buying red, that is one I purchase extra of, as well as black. Just a thought if you are starting. Also, those nice little fat quarter bundles are always a treat to have so you can accumulate different fabrics in your stash. Have fun building that stash girl.