Toothpaste and denture cleaning products cost more than they did a few years ago, largely because manufacturers are trying to sell us premium whitening products. But a good, old-fashioned cleaning is still inexpensive:
Dip a wet toothbrush into some baking soda and then brush and rinse as usual.
For dentures, retainers, and mouthpieces, dissolve 1 tablespoon baking soda in 1 cup water.
Let the object soak for a half hour, and rinse well before using.
Bonus: This is a non-toxic solution and kids won’t be tempted to swallow baking soda the way they might with commercial, candy-flavored products.