I think I bought the pantone color set off ebay for around $65 or so. That was the cheapest I could find it. It was the one that is like old spark plug feeler gauges. You get two strip sets. One gloss and one flat. As was stated, they are designed for printers, not painters, but they are more mobile than the side of the game.
The problem is, they have NO whites in the set. For that, you just have to get a bunch of paint cards at the local Hardware store (lowes, Home Depot etc.) to cover an array of off whites.
I prefer Rattle can (spray paint) to mixed latex colors and there are no real matches that I have found to the aged yellowed cabinet paint. The closest I found was Heirloom White which is also a Satin finish so you don't get that super glossy look. It won't blend with color on the same side but it is a close enough match if you do the entire surface and stop at the corners (like doing your front door area). All the other Ivory type colors seem too "tan" to my eyes - too much brown. For touch up using good Old Testers Model Paint (Oil Base Enamel), it is mostly white, a tiny touch of black, and a small touch of yellow to make a good match for small area touch ups.