Northern Sport of Ontario produces lines for private brand resale. That's what the Global Dorber lines that RickZ mentioned are.
I have one of their lines on a reel right here on my desk that I bought sometime back in 1981-82. I don't use it anymore, but I could. No cracks.
I get mine from a shop in Denver ... $9.50. They say that the lines are factory seconds but I've never seen anything to justify that.
I've got 7 or 8 of 'em... no issues.