Paint strainer bags for 5 gallon buckets:
EDIT: Just yesterday, I sewed 12 bud bags (30" x 24") from Agribon AG-15. On my rickety old sewing machine, it required less than 3 minutes per bag, including measuring and cutting the fabric, and cutting the Tyvek tags.
Remember to label the variety on each of your bags, somehow.
From Ebay: "Extra Large (26" x 22") Reusable Drawstring Brew in a Bag" only $10, and still smaller than my bags. If you needed many of those, you could pay for not only the Agribon, but the sewing machine as well.Those look like the grain bags from the homebrew store, but at half the price.