Amidst the multitude of plastic bags, one may struggle to finding reason and meaning for the wretched things. Well.. Don't stress, here's a cheap alternative to pricey boot holders and inserts.
Begin stuffing the bags inside your shoes, making sure they fill out the shape evenly.
And voila! Your boots are now free/standing and independent, retaining their natural shape and style. You've also found a smart place to store your plastic bags!