When is the best time to purchase a plane ticket for the lowest price?

I would like to know how far ahead I can buy a plane ticket and what the savings would be, on average of course. ThanksWhen is the best time to purchase a plane ticket for the lowest price?priceline.com And I think a month in advance but i'm not sure..When is the best time to purchase a plane ticket for the lowest price?Middle of a week that is not close to months 1,2,5,6,7,11,12 and doesn't have any holydays near.