The rarest and most costly is the 222- a freearm machine that costs about $600 plus. The 221 came in 3 colors- tan which is the rarest, white, then the common black. Prices vary a lot, but about $275 for a decent black with case and accessories, to about $475 for the tan. For just sewing and enjoying- buy what you can afford that is in good condition, and try it out first. For investment- the best condition and rarest win.