I couldn't decide between all the bag and size options out there. Luckily my wife just bought a sewing machine so I put her to work to make all kinds of bags with different sizes and fills. With the amount these bags cost, and if you can't meet up with a buddy who has the ones you're interested in...making your own will give you a great idea of what you need (and more importantly what you don't).
The dimensions are all listed on-line and making a couple bags will pay for itself very quickly (sewing machine included).