If you buy a "real steel" carrier built to mil-spec by a real military company, your carrier will outlive any airsoft carriers in my experience. Khaki, black, and ranger green are unpopular colors these days, so you can get better used and sometimes new prices on those colors.
Here's a few popular, well built, medium (10"x12"ESAPI plates) and affordable carriers for your consideration:
http://lbxtactical.lbtinc.com/0300cLBX is an airsoft focused off-shoot of LBT, LBT makes decent real steel gear and their airsoft stuff is very comparable to their real stuff.
https://www.tacticalassaultgearstore.com/gear/plate-carriers/crye-precision-jpc-jumpable-plate-carrier.htmlCrye's JPC is famous for it's skeletal cummerbund which provide better airflow and weight reduction. Their quality and customer service is legendary.
http://www.ar500armor.com/banshee-plate-carrier.htmlShellback Tactical (SBT) is an off-shoot Tactical Assault Gear (TAG). TAG's products last forever, SBT's quality is very comparable to TAG and the Banshee Plate Carrier has become one of the most well known budget carriers on the market. [EDIT: TAG has a new PC called the Vangard, can find it for around $200 on ebay and such, looks nice]
http://atstacticalgear.com/ats-aegis-plate-carrier-v2/Nice carrier by ATS. ATS is a real steel company, but their quality is more on par with LBX. The mesh interior makes for good airflow.
If you want to go the used gear route, higher end carriers by Tyr, First Spear, Velocity Systems, Eagle Industries, MSA, and Paraclete can all be had in the $100 to $200 range. Just be careful, if it's been used over-seas on deployment it will show heavy wear from daily use. Older model carries tend to focus more on PALS/MOLLE space rather than airflow and comfort; newer model carries are more “high speed”. Like Gimpalong stated, don’t buy a carrier just because it has a ton of pouch space; the better you get the less gear you actually need to play.