And thank you both for serving! My dad is active in the Army.
You can use Checkoutmycards.com, they use Beckett values as well. Only problem is that they don't have every card, so they might not have prices for all your cards.
Seeing as the magazines do not have every card in them, and the fact that you have internet where you're based, I'd suggest Beckett online. That way you are sure to get pricing for every card you have.