I didn't say you had to buy it through Amazon. I just said if you want one they have them for about $10.
Buy them from whomever you like. Support your local shop. Buy one from Retrogression, whatever. At most it's like $15.
I just wouldn't spent upwards of $40 for a chain when a $10-15 chain works great. I've had probably 4 of them and never had an issue. They run quiet, look good and are cheap. What more do you want?