A man just finished painting his house and goes to the hardware store to get something more. He finds what he is looking for and the clerk says "One for $1." The man replies, "I need 600, so here's $3." What did he buy?

Apparently they bought 3 of whatever it was and stole 597. This was just his fancy one-liner before he held up the store. Haha, I feel like this answer fits the description really well but it probably isn't the right one.

The man needed to put his address on his house. 600 was his address. So he bought 3 numbers. A six and two zeros. Each number cost his one dollar.