This was not my idea, it was sent to me; 

Use plastic bottle tops (water, coke, milk plastic bottles etc) to seal bags of dry food and cereal in, cut off top, feed though the cut bottom, out the top, over the edge and screw on the bottle top, see;

Well if it wasn't you, someone is a clever bugger, I certainly will try that idea.

Me too......I'm surprised nobody has thought of it earlier, a great idea for us on the road (and at home too).  To cut the tops of bigger bottles (eg; Milk bottles) you could use a serrated knife or something similar.

I think I first read about this idea in a Grass Roots magazine, but it really does work well - I made two up and we use them all the time. One idea - to economise, I buy the bigger boxes of cereal when shopping, and put it into a plastic cereal container. However, it never all fits in there, so I put the little bit remaining into a plastic bag and seal it with the bottle top idea. Works a treat! I use all that first, and then start on the big container.