They used to sell them over the phone but I do not think you can do that way anymore and you just buy at guest services at one of the parks when you get there. Also, buying in advance was not the better choice anyway because they would send one that started before you actually went to WDW. You buy at the park and it statrts when your purchase and is good until the end of the thirteenth month thereafter, e.g., buy anytime during Feb 2015 and it is good until March 31, 2016.