About the sale of the AOE3 DE on either steam or Microsoft store

I'm an ardent player of both AOE2 and 3, but due to my personal reasons I didn't get a chance to purchase AOE2 DE last year. I know that AOE3 DE is under beta right now and will probably be released later this year. I'm recently thinking of purchasing the AOE2 DE, but I would like to know whether if would be cheaper on either MS store or Steam if I purchase the bundle of AOE2+3 DE (if there is one) once the AOE3 DE comes out.