I _always_ play on Marathon. As a result, the Religion warfare can last for millenia. In my current game, right around 200 A.D., an Apostle costs >3,000 Faith. And by the year 1000 A.D.it's likely to cost >4,000 Faith. In my opinion, anything in excess of 2,000 Faith is way, way too excessive. (Even then.....) There needs to be some reasonable cap put on the price tags of religious units.