We offer two kinds of passes: per-day and weekend.
Per-day passes are only offered at the door and they're $30 each. Our full weekend passes cost $50, so it would be the same price either way.
If, however, you wanted to pre-register, you could get a weekend pass for $45 (you have until Aug. 15 to pre-register). By doing so, you'd save $5, get a niftier badge (with your name printed on it and everything), and if you opted to show up for a few hours on that third day, you wouldn't have to pay any extra.
For these reasons, I recommend getting a weekend pass and pre-registering if you can.