There are numerous bus passing Aguinaldo Highway which is the main road in Tagaytay. If you would like to be dropped off at Buendia, take the bus with Taft LRT Buendia signboard. While, if you would like to be dropped off at Cubao or anywhere along EDSA that is along the way to Cubao, take the bus bearing Kamias Cubao signboard.
The fare will not exceed a hundred pesos. Travel time will be a little bit longer compared when you take a private vehicle since the bus passes through Cavite instead.
Good luck and enjoy! :)