Last week general admission for three-day and single-day passes were all taken, and as of earlier this week even the VIP tickets were unavailable.
The festival runs from Aug. 9 through 11.
Tickets were priced between about $100 to $545 for some packages.
Since selling out, demand on ticket sites such as Craigslist and StubHub has gone up, with some one-day passes offered for up to $195 for general admission.
This year's line up includes headliners Paul McCartney, Nine Inch Nails, the Red Hot Chili Peppers, and Phoenix.