Arsenal are just about the most expensive team to go see in the world.
Arsenal tickets tend to be sold through season ticket holders, so your best bet would probably be touts or various sports websites which rent the tickets off ST holders missing a game.
Why are you being an A**hole and expecting people to not reply back with troll responses? stfu and learn how to use google. If you don't know how to find out how to buy tickets using GOOGLE, I think you're the incompetent one...
Think away tickets are meant to be cheaper from this season onwards if that's viable, if you're not up for getting a membership People usually advertise spare tickets on Twitter