Convert a child trailer to cargo duties. Find one on craigslist, take off the nylon, and put a floor on it. I have a Bell trailer, it'll haul ~200 pounds, is 15 to 20 pounds in weight, and the tongue folds down/wheels come off to make it more compact. If you go this route, I strongly recommend the Burley hitch set-up. For under 100$ you can have a decent trailer with a decent hitch. This is what I did for a few years before upgrading to a BAW trailer.