Gray Card

I am just about to order some lenses from B&H and I would like to throw in a Gray Card.
Which one would you suggest?

Think cheap, but not too cheap, pls..

There seems to be a massive shortage of Kodak gray cards these days.
Adorama, B&H, Calumet and 2 of my local shops are out. Are these things going for the war effort of something?

I ordered the Delta from B&H, but I can't speak to the quality, though they are gray.

If you're just using it for exposure, not for white balance, does it matter if it has a slight color cast to it?

I just picked up the Novoflex Zebra White/Grey card. It was $20. BH has them and are readily available.