Not too long ago I was browsing eBay, like you do.
And I ran across a lot of Cascade Venezia. It was 6 skeins in a dark green colorway called, "Shamrock." It was only about $5 per ball, which I considered to be a good deal and so into the cart it went. I had no plans for this yarn. And it wasn't until I was doing some math later on that I realized that actually 6 skeins might not be enough for a sweater for myself. I ended up casting on for my 12 year old niece instead.