those plastic tubes are one of the best and cheap answers to food storage that have come along in awhile.i put just not the peanut butter and jam into them but also dry milk and sugar.
unscrewing a cap and shaking a bit of sugar into the AM coffee sure beats spooning it out of a jar.
tip..the bars that close up the end have a pointed tip in them to help the bar fit and slide to close the flap.i cover those with a bit of tape so they don't punch a hole in another Zip Lock.