While I do not want/need body armor, I was still curious of the price. So looked up that level 3 Spartan Armor plate and it is anywhere from $385 to $685, depending on the materials. Which made me look up how much Kevlar was needed to stop a 5.56, had he used it. So here is a video from a soft armor (loose layers sewn together) manufacturer testing just that. They got up to 45 layers of Kevlar before it stopped the round.
Still, you can buy Kevlar for
$50 a yard (50'" wide), which means you could probably make a riffle resistant, yet rather thick, chest "plate" for less than $300. No clue if pressure molding it with resin would increase or decrease layers needed or thickness (if it needed more layers).
