You’ve bought a ticket and applied sunscreen, but where are you going to leave your car? Unfortunately, unless you’re staying at one of the nearby hotels, there isn’t a free or convenient option.
Rock in Rio organizers recommend taking the Monorail ($22 for a two-day pass), which will be operating on special festival hours. They are also offering two-day shuttle passes for $25. If you want to avoid public transportation, the Stratosphere is offering $30-a-day parking and the SLS is offering $40-a-day parking. Or you can always just take the bus.