What is the plastic thing called that holds price tags to clothing merchandise etc?
It is a swift attacher!
What is the plastic piece that holds the lines to the expansion valve on a 1995 Toyota Camry called?
If you use one of the old-fashioned ones, it's simply a piece of wood with a slit in it. It works by sliding it onto the clothing and the pressure of clothing + clothesline holds the clothing onto the line. If you use one of the spring-operated pins, the pressure from the spring holds everything in place.
An Easel. The surface, sometimes a board, but these days more often than not a piece of acrylic, hard plastic or even glass on which an artist holds and mixes paints (acrylic or oils taken from a tube), is called a palette. The stand or support that holds the surface to be painted, be it stretched canvas, artist's board, or other acceptable ground is called an easel.