Buying glue is cheaper in big bottles, but it's not convenient to use that way. So you can pour it into the usual bottles, but they have a tiny opening and it's slow and messy to fill them. Plus they have a small opening out, and can not usually be closed 1 handed. Finally, when the glue runs low, you have to tip and wait or shake the glue down to the opening. Here's one way around all that.