Visit sixflags.com, specifically this link: https://www.sixflags.com/national/coke2 to access discounted Six Flags tickets through Coca-Cola. Or visit Groupon.com and search for Six Flags tickets to find discounted rates.
For a third option, visit http://www.retailmenot.com/view/sixflags.com to find additional discounts on Six Flags tickets.
Some grocery stores and recreation centers across America also have partnerships with Six Flags. Call or visit a local grocery store or civic recreation center to find out if it offers discounted Six Flags tickets.
Many packaged Coca-Cola products also provide discount coupons for Six Flags tickets in the summer. Visit a local grocery store to look for this specifically marked Coca-Cola packaging.