Honestly, armor doesn't cost anything. You buy the cheapest armors, triple enchant or quad enchant them, then sell them before they break for a profit. All it costs you is a few mp points to enchant, and you can buy 2-3 more pieces for the price you sell them for. And they'll negate a lot more than the 3 attacks cex defense does.
Plus doesn't Cex defense consume on ranged attacks?