Regal Plastics - Houston, TX
1700 Wirt Road
Houston, TX 77055
T: 713.957.8541
I've dealt with them a few times. They generally deal in large quantities, and they've given me free 'samples' when I explained whatever art project I was working on. Once or twice when I couldn't find what I needed in their scrap area they charged me a couple bucks to get me what I needed.