My problem is I'm cheap
If I stay on the expensive side of the store everything is laid out nicely and labelled with the contents of the yarn, the yardage and the gauge. BUT, I go straight to the clearance section and it's organized like a garage sale! There are bins everywhere and nothing is clearly laid out! At least the keep similar yarns together, ie. ribbon, cotton, wool. So I end up having to look through every individual ball to see what I'm looking for. Then I get stressed out and leave.
What I'm trying to substitute is Katia yarn. I have an old pattern book with some cool tops I want to knit. The yarn has since been discontinued, but it's very hard to find current Katia here in Canada (that isn't $14 for a dinky ball). I have found some on Ravelry, but am still looking. Most of that yarn is ribbon yarn too.