Was his "truck" a wooden cart pulled by a buffalo? LOL
Just to play devil's advocate, I could see a lot of trucks costing 5k or under. An ar15 could easily get there, especially once you include an optic. A lot of larue, noveske, or KAC models get you pretty close already. Now, if you're just using a red dot or acog, add 500-1500. Throw on a US Optics and that is an expensive rifle.