I currently own a Glock 21C (.45, compensated) and a Glock 26 (9mm). My wife and I share the G26 for carry, but she is carrying so often now it is time for a new CCW. I am looking at the G30 and am considering trading in the G21C to offset the cost, since I just got laid off. How can I find out how much the G21C is worth? I am just looking for a ballpark here to decide if it is even worth trading it in. Thanks!