Well, you can buy "laminating sheets" at most office supply stores, which are basically sheets of clear, sticky backed plastic. They will do the job but are bulky and stiff.
The way I have found that "laminates" a piece of paper, and gives it a fair amount of water resistance, is to cover it with a layer of clear plastic packing tape, the kind that comes in 1 3/4- or 2-inch wide rolls. If you do that to the front and back of a piece of paper, it'll have a lot more wear resistance and be able to put up with a certain amount of abuse. It's also easier to fold a sheet of paper after you laminate it with the packing tape.