Yes, Dan is right about that. You don't need to have plants to come to the swap. Remember, these people are giving away plants because they have too much and don't want to throw them away in the garbage. Many are hard to find or rare plants! So just come already if you have the time
Another thing is, once you join the club and become a member you can ask any other members any time for any plants you think they may have(sorry for the run-on:P) You don't really have to call for any 'Plant Swap' like Luis did. This is just one of the many benefits members get, in addition to learning a great deal more about this hobby. So, you don't even need to wait until the meeting to trade plants. Like I said, feel free to contact any of the NASH officers or members to inquire about any plants. More than likely, one of us is bound to have the plant you are looking for.
Other than that, have a fun and a safe weekend!