Just had a quick idea...why don't you offer a tier with a 12 month subscription, so they get a new sock every month. That'll be popular I'm sure! If it gets you to your total, you should buy an advert on my gifts site!
Just want to point something out, which is don't you find it strange that a KS owner would post their listing in a thread and then never return to answer questions/reply to stuff about it?