Robert Kaufman does have sample card for Kona Cotton. They are usually given away at wholesale shows. You might want to see if you are able to contact them explaining why you need one of them. $60.00 is a little excessive for something that is given out for free. (or they use to in the mid 90's) Most sales rep of fabric companies have fabric samples to show clients that are small cuts of the actual fabric.
Just a note, I just received my first Hancock;s of Paducah catalogue. On the last page, they have pictures of the fabric swatches and to me who dealt with Kona Cotton, the colors appear to be very accurate. They also have a swatch card for sale for $29.98. ID number is KC CARD. Their number is 800-845-8723. They do post their specials on the board when there is free shipping. FYI Good Luck !!