Lightweight, water resistant back pack?

[RainK]

First trip without a stroller......so my hunt begins for a lightweight somewhat waterproof backpack / slingback bag.
All we need it for is camera, wallet, sunscreen and water/snacks.
I really don't want anything heavy or bulky and need it to be comfortable for all day use. Oh, and inexpensive.

Suggestions?

 

[AintGonaGrowUp]

I just use a small backpack that you can pick up at Wally-world. Go to any sporting goods store and pick up what’s called "camp-dry". Take your pack outside and spray it. (Put on a couple of coats) It will smell funny to begin with but once it dries it will go away. I haven't had anything discolored or left oily after spraying it.

Another thing that I have done, I pack a small draw-string plastic bag. (The ones you get when you shop at pac-sun...ect...) It stuffs in the bottom of my pack. When I go on a ride or it starts to rain, I pull out the bag, drop my pack into it, synch it up, and go!

 

[Clare Voince]

I've never used it myself because I prefer cross body bags, but a lot of people here swear by the baggalini messenger:
http://www.amazon.com/Baggallini-Me...YMXS/ref=sr_1_1?ie=UTF8&qid=1305523489&sr=8-1