Here's a definition of mill ends from twojunemoons, which sells batches of mill ends from excellent companies on ebay. This auction was for 1530 yards (1 pound 2 oz.) of Cherry Tree Hill sock yarn; the price was just under $20 US.
[COLOR=#000000]"Mill ends are the end runs of a lot. They are not labeled with color or dye number and are sometimes several skeins tagged together.
Other than that, these are first quality yarns."