I BS'd my husband into the 800 dollar a year fee by explaining ( truthfully ) that I myself me and nobody else is the obstacle to me getting more money per customer canvas slipcover purchase.
If I had made just 16 dollars more per canvas cover I sold I'd have it paid for. And, if the covers are well illustrated I should be able to get 16$ more each many times over, since I go in and sell a job no one has previously considered.
If they saw the canvas laid out they might also say no to the canvas but tell me they'd come better prepared with COM which I do also.
My DH was very clear he didn't want me to do a greater number of covers in a year. I know I can get more per cover, and I know web customers are less apt to price shop if it's unique and custom.