How to turn a mason jar into a spillproof cup with straw (for ~50 cents or less!)!
mason jar lids (I use wide mouth ones)
a drill with a 3/8in drill bit
rubber food grade grommets ( Search etsy or google for "food grade grommets"). See size photo below.
These are SO easy!! Don't be afraid to jump in there and get some made! Go, go, go!!