<font face="Comic Sans MS"><font color=#006400>Yes, and there are a few of them located throughout DL. They are marked on the DLR map you get when you go in the parks.
There are a number of pin carts around both parks and many of the stores have pins as well. The big pin trading station seemed to be in Tomorrowland at DL. There were quite a few "serious" traders there. There are tables set up outside the store where you can display what you have. I didn't hang out much to see what was going on as I prefer to trade with the CM's (much easier knowing they'll trade just about anything!).
"Is there somewhere there to get discounted trading pins,to start trading with??"
Not that I saw. I found some on sale at the Disney Store before I left. If you're going after the holidays I would check the Disney Store's after Christmas sale to see if they have any.
For trading, pins must be stamped Disney on the back and be enamel so you need to be careful about buying discounted pins other places that might not be tradeable.
When I ordered from the Disney Auction site on Ebay, they sent me a neat Lilo and Stitch pin free with my order. It had small Mickey heads (rubber) for pin backs! Is this common now? Haven't been to WDW in over 2 years and never saw that before!