I've been ordering my boxes, cello, etc. from PaperMart. They are awesome! I just priced out their ribbon -- 100 yards of 3/8" grosgrain (solid colors) ribbon is $3.98/roll! I was shopping Hobby Lobby during their 50% off sales and getting 5 yards for $1.
Their shipping for heavier items is expensive, but I would think if you live on the West Coast, it would be a lot cheaper to ship. (They are located outside LA.)