How much yarn would it take to make a 10-12 foot scarf? Crochet, not knit.?

[Cecilia Dillon]

I think the question says it... probably would be with heavier home-spun yarn. I need to buy yarn so my friend will make it for me...
I'd want it to be pretty wide, maybe 6 inches, and with woolen yarn, I don't do artificial.