A quick search shows several of these PSA 9 cards available on eBay for $30 right now, which I’ll be honest I thought was high...
I need look into it more, but I think I saw somewhere that there is a difference between the normal cards and the "Tiffany" cards...
it has to do with the glossiness - the Tiffany ones, both back and front, are more glossy than the standard card. If you have a keen sense of touch, you can feel the difference between the two as well.
here is a Tiffany McGwire on the left and a standard McGwire on the right.