You'll have a good time, even if you don't buy anything, you'll still have a good time.
What I do when I go to a train meet, I'll walk around, check out all the tables. If I see something I'm looking for, I'll make a mental note where I seen it and the price. Chances are someone else might have the same item and possibly cheaper. On the other hand, the first one I seen might just be the only one at the meet. That's the gamble of waiting and hoping to find a cheaper one.