If you ever decide you want to build your collection of threads, this is a great way to do it. You can pick a club that ships you cones or spools and get new thread for sewing, quilting or embroidery every single month.
What else did I get in the mail? Bobbins and bobbin cases for my long arm. You don't realize how important extras are until you don't have any. I ordered these from eBay. Ten more bobbins and five more bobbin cases. I'll be ready to sew for ages!