Why do you want a plate carrier? Its pretty pointless for the most part(airsoft wise anyway), and because they are meant to hold armor they get a bit more expensive. If you are only looking to spend 100 bucks or so, I recommend a RACK of some kind.
What are you looking for as far as pouches? You could get a rack that holds mags from diamondback tactical for about 60 bucks, then order a few extra pouches from tactical tailor(who are having a sale, so you can get stuff from them for cheap). How many mags do you want to carry?