Play A Game Of Checkrs With Datacolor
Mine's an old model made by a respected old manufacturer. It was made while Elvis was alive but is still going strong - as it gets stored carefully in the dark between uses*. It cost me a surprising amount of money back then and I am glad it is still going strong - I like to get value for money.
Well, if you would like to get better value than that right now in a colour/B&W reference card may we suggest the Datacolor Spyder Checkr 24. It is made in a lot sturdier material than my old one and in a more convenient size - 5 x 7. You can haul it in any camera bag for a quick ref shot in every new situation.
There is also a downloadable SpyderCheckr camera calibration software and support materials note on the sleeve that protects the panel. Not sure what they expect you to do but all I have ever done is look carefully at the results on the Polaroid/print/screen image and then take appropriate measures. Call it chromatic blundering into the furniture, if you will, but so far it has worked.
$ 65 means you CAN afford this.
* If they had stored Elvis in the dark between uses he might still be going strong too.