Best way to find is to ask for anyone selling their stock set in the Lancer EX thread in tsikot.com. Also it helps to check the MitsuLancer website forum for Lancer EX owners upgrading there wheels.
link: MitsuLancerPh, Inc. The Premier Lancer Enthusiast Club of the Philippines - Login
Typical price for an almost new set of four with no defects/scratches is P25K while a set with very minor scratches can be bought at P15K.