When I set out to find something to keep my sleeping bag and change of clothes dry I turned to dry bags. I wanted to test them out first and see how they work and if they actually work. Instead of spending a bunch on a bag to see I opted for the cheapest route on ebay on their largest bag available. I ended up with a 70 liter Blue Field dry bag.
I must say... for 6.50 I am truely impressed that the think is actually waterproof!! We ended up tipping our canoe and this floated down the river a ways and all my gear was dry. Best 6.50 I have spent on waterproofing. These come in various sizes from 5L all the way up to 70L. They also come in a variety of colors.
The only complaint I have about these are they are really thin. I am always checking for rips or afraid i am going to rip it. Other than that two thumbs up here!