At the Great Lakes Fiber Show this past summer, I bought two bags of alpaca seconds (the part of the fleece that's not first quality). They cost about $3 per bag. I wanted to use the fiber for felting because alpaca tends to felt up really nice and thick.
After de-hairing and washing close to six ounces, I carded it into bats. I had about four ounces of black fiber and close to two ounces of brown fiber.
Initially, I wanted brown on the inside and black on the outside, but the black ended up pretty much taking over everything during the felting process, including the white wool accents I had placed around the edges of the openings and as design elements coming down off of the rims.
I felted around a resist (template) which I removed when the felt started to shrink and then continued felting the slippers around my feet for a custom fit.
Here are the slippers as they were drying over a heat vent, note how hairy they are:
Once they were dry, I shaved off the fuzzy, hairy-ness with a disposable razor. Below, the slipper on the left is still hairy, the slipper on the right has been shaved:
Below you can see both slippers, dry and shaved. I've ordered some soling material from this Etsy shop - www.shoeology.etsy.com - to put on the soles. I don't want to slip in my slippers!:
You can see how much the fiber shrinks in felting, the big white thing is the resist that I felted the fiber around at first. The slippers ended up much smaller: