The most popular way to store items such as extra clothing and various accessories while camping has been stuff sacks. I was amazed at their prices, often over $30, and wondered why plastic bags from your neighborhood grocery store couldn't serve the same purpose. I came to find that stuff sacks claim to serve two additional needs for camping bags:
1) They need to keep everything dry - very important for clothing
2) They need to compress down to a small size to be able to fit into your pack.
3) Some bags claim to provide extra stitching and odor control for keeping out critters.
Its clear that both of these needs are really only essential for clothing and food. I personally decided to use a bear-proof container for my food/suntan lotion, because I didn't really believe that simple stuff-sacks could keep out rodents, which are typically your biggest nuisance, and to provide a bit more food security and isolation.
So that leaves clothes, and everyone who has camped while it rains or snows knows that if your clothes get wet, you're pretty much screwed. It was in thinking about 2 things, cost and dryness, that I thought about the ultimate solution for keeping moisture out ... Vacuum sealed bags.
Step 1: Vacuum-sealed Bags
I had found vacuum-sealed bags made specifically for camping, but they were ridiculously expensive, as almost all camping gear is. BUT, standard traveler's space-saver bags are very cheap. I got a set of 5, each different sizes, for $20 at walmart, but you can find them online for even $5. You really only need 1 smaller-to-mid sized bag for your camping purposes.
The crux of this plan however, is how do you actually vacuum the air out while you're out in the woods.