weapons. engineers have designed the barbed wire. the normal protection, wherever they go. reporter: these 7,000 u.s. troops sent to the border will be missing thanksgiving with their families. the pentagon has been unwilling to answer questions about how much this deployment will cost. the pentagon will be paying tpoeurt. early estimates point to a $200 million bill, which some worry will mean less money to fix planes and maintain equipment. we will update you on costs as they become known. obviously, capturing the cost. reporter: unlike a deployment overseas these troops are not getting combat pay. their living conditions are spartan. most are living in tents and eating prepackaged mre s even though grocery stores are nearby. at first the name of the mission