You also face the problem of not much variety unless you have a large stash and can cut from that.
Do you have any friends that quilt and would be willing to swap 10" squares? If you do buy a variety of fabric, make sure it's in 1/3 yard increments. If you buy a 1/2 yard you will only get 4 10" squares (18" X width of fabric) and 1/3 yard is 12" X width of fabric. Don't buy fat quarters (18" X 22") or skinny quarters (9" X width of fabric). Do you have any discount fabric stores around you? Also, let the person cutting the fabric know what you are planning on doing with the fabric. They (if they are nice) will be more careful cutting the fabric. I bought skinny quarters from a well known fabric store (not a quilt store) and the elbows were so bad I only got one 2 1/2" strip out of them when I should have been able to get 3!