To die, especially in combat; most likely from the idea that a dead soldier's death benefit would serve to pay off his family's mortgage. Often shortened to "bought it."
There is, however, a story in the Bible about buying a farm--well, a field anyway, as told by Jesus in Matthew 13:44:
"The kingdom of heaven is like treasure hidden in a field. When a man found it, he hid it again, and then in his joy went and sold all he had and bought that field."
What I hear Jesus saying to me through this verse is that He himself is a great treasure--greater than any other treasure I could possibly find in my lifetime. Everything else falls by the wayside in comparison to reaching Him. To "sell everything you have and give to the poor, and you will have treasure in heaven. Then come, follow me" (Luke 18:22) makes complete sense when compared to the uncomparable Treasure that I seek. To "run with perseverance the race marked out for us" (Hebrews 12:1b) and to "press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus" (Philippians 3:14) should be my mindset and the mindset of every disciple of Jesus. Oh, that I would realize His value! Oh, that in my joy I might buy the farm!