http://www.mycokerewards.com/instant-wins/united-airlines-instant-win/50110
click section 5c in the rules for free entry
28 Prizes: A United Airlines® Ticket Certificate, terms and conditions apply. Valid for two (2) round trip tickets for flights anywhere United Airlines® flies within the 48 contiguous United States, Alaska, Canada, the Caribbean and Mexico. Certificate is valid for two confirmed Economy (K) class round trip tickets (economy promotional fare). Space in Economy (K) class of service is capacity controlled and may not be available on all flights or dates. If issued for one-way travel, any unused portion will be forfeited. Offer valid only on flights operated by United and United Express®. All travel must be completed by March 1, 2015. Winner is liable for all applicable taxes, fees and surcharges. Certificate may not be used in conjunction with any other award, discount or offer. This offer is subject to any government approval and is invalid where prohibited by law. The Certificate is non-transferable and is void if sold or exchanged for compensation. If recipient books flight by calling United Reservations, there will be a Reservation Ticketing Service Fee. There is no fee to book and redeem on United.com. Not eligible for denied boarding compensation or MileagePlus® mileage accrual. United reserves the right to change the Terms and Conditions of this offer without prior notice. United’s Contract of Carriage applies to all travel, except to the extent modified hereby. Additional terms and conditions apply. Approximate Retail Value (“ARV”) of each Grand Prize: $700. The ARV of prize may vary based on winner’s choice of flights, airfare fluctuations and distance between departure and destination. Winner will not receive difference between actual and ARV. Winner and travel companion are solely responsible for obtaining valid passports and any other documents necessary for international travel, if required. Limit: 1 prize per person. Total ARV of all prizes: $19,600.My Coke Rewards United Airlines Instant Win