Coffee sacks for gardening

Possibly a very cost effective and easy solution for container gardening would be coffee sacks or other burlap bags.
I got these and many others from my local coffee shop for free. I see a local ad on Craigslist for $0.50 each for more.
You can shape them how you want or build a simple would frame to hold a shape.
They will break down over time obviously but you can deal with that as you see fit.