Where do you find all those 3 oz. or smaller sizes for liquids, gels, etc. to get thru check-in on your flight?

Seems the drug stores don't stock this size for the products I use. Where's the best place to find those travel size items, like shampoo, gel deodorant, toothpaste, etc., to get through those airports. How many bottles have you fit in those one quart bags?