There should NOT be a cost for laundry. The machines do have coin 'slots' but you do not need to put any thing in them, just push them in and you should be good to go. If you put money in, it will take it!!!
No, we used the laundry at the main pool in September and there was no charge. I think this one is one of the nicest laundry rooms I have seen at any of the DVC resorts.