Kona is a trademarked 100% cotton broadcloth made by Robert Kaufman, a fabric mill. Kona cotton was introduced by the company in the 1980s in response to the rapidly growing quilting industry. The thread count for kona cotton is 60 by 60. This high thread count is what allows kona cotton to balance durability with a soft hand and light weight.
Combed cotton is typically more expensive because in the combing process you loose a greater number of fiber, thereby reducing the amount that is made into fabric. (an addendum to crafter2243 answer)
I do not know if this helps. This is describing it in
What’s is Brushed cotton bedding?
Brushed Cotton means that the fabric has simply been brushed so that any excess lint balls and fibers are removed, resulting in beautifully smooth, soft sheets.
What’s the difference between brushed cotton bedding and normal cotton bedding?
Brushed Cotton bedding is cleaner, flat, and a little smother feeling that normal cotton bedding.
If I remember my home economics correctly, the long cotton fibers are "combed" before it is made into yarn, taking out the shorter "prickly" fibers and "trash" which makes it softer and aligning the long fibers to make them durable. This takes out some of the volume when making the yarn, so it ends up being a little more expensive.
Actually it was cheaper than Kona on the site. So hard when you are buying on line. Can't reach in a feel the fabric.