Gus has a good idea.

I found these in the Toronto area.

http://toronto.en.craigslist.ca/tor/bfs/2741137379.html



http://toronto.en.craigslist.ca/tor/tls/2704123906.html

Sure you have the upfront cost of a container (unless you lease/rent), but when you're done you can sell it. And I bet your cost to lease a piece of land will be cheaper than a storage unit.