None of the on-site WDW resorts charge to self park. You won't need to show your DVC card. You can choose any open spot in the self-parking lot. During busy seasons, guests who are just visiting may receive a 3 hour parking pass. This is to discourage people from parking at a resorts when their intention is to visit one of the parks.
Valet parking is available at the BC/BCV. It's free for DVC members and it doesn't matter where you are staying. For that, you will need to show your DVC membership card. As you know, a tip is appropriate.