Ah, Temptation on Every Front

So after going through this whole process of getting my apartment exactly the way I want it, I now never want to look at pictures of it or do any decorating projects for it again, or at least like six months or something. But somehow my resolve just never sticks around.

I've been using my exercise ball for the past 6 months or so as a desk chair: 1) because I never actually use it as an exercise ball, and 2) I'm too lazy and cheap to get a chair that actually fits there. The desk is an odd height, so the dining chairs don't actually work with the desk at all.

So I've been eying this stool from CB2 for a while now, to replace the exercise ball, but I've resisted, seeing as how it was previously $130 + $20 for shipping, which is way too much, considering how much I normally spend on furniture. But it would be perfect, because it's adjustable, very attractive, and wouldn't interfer with the view of the TV, like a chair with a back might. I've resisted the temptation for about 4 months now, but I just went to check on it, and it turns out they have free shipping and it's $100 on sale...what to do, what to do... I'm very conflicted.