You can just send STEEM to @catnet and you'll get CAT back at the rate of 0.01 STEEM per CAT. I process these "under the counter" sales manually so it might take a few hours but there's a rumor I am giving a 10% bonus out of my own pocket.
These direct sales contribute directly to building value behind the token.
But, you can also get them much cheaper on the open market on steem-engine. Though that doesn't contribute much "value" it does help to move the "price".
I have a whole post about value and price coming out later, I promise it'll probably get even more confusing ;)