When I took lessons, they didn't "require" you buy from them but they sure pressed to get everything from them. The owner even yelled at me a few times because I bought things from Amazon and not from her. Needless to say, I haven't gone back since the 2nd time she yelled at me.
A few months ago, I had a quilt quilted from a local shop near my daughter. I gave her the top and batting. I didn't have a backing or else I would have used that too. There was no problem using my own things. They got their money with the quilting.