Knit Pick's new yarn Chroma comes in both fingering and worsted. It is a single ply yarn with 396 yards in a skein of fingering, 198 in a skein of worsted. It's $8.99 per skein.
Ever since Chroma was released, I've been itching to try it out. I probably won't use it for socks since it is single-ply but it would be great for things like scarves, hats, shawls, etc. The colorways I really like are listed below, my favorite one in bold.