I'm not sure about a trade page for CP on this site. There is another site I use which has a larger group of CP growers including some trade/buy/sell section, called flytrapcare.com

Also being that you're in / around south Texas, you may also have some luck finding some interesting CPs at http://www.petflytrap.com which is near the Houston area. I'm not sure exactly how far you would be from there but when I'm looking for plants, I'd drive a certain distance to get them!

Otherwise, I've also found some Nepenthes plants at Lowes, as well as Nepenthes and buttworts at one of my local nursery chains. That chain is also related to Cornelius nursery chain in the Houston area. http://www.corneliusnurseries.com/

Go on Facebook, lots of very active CP groups!

I second purslanegarden. Flytrapcare has a great group of people, lots of info and sales, trades and giveaways. There is also another forum that's called carnivorous plants in the tropics that is more nepethenes based.