Bribes?

Cody and Carson have been fighting over who gets to climb into our mini-van first for a few weeks now. It gets on my nerves quite a little. I have been refusing to mediate these fights for the last few days assuming that they would come up with their own solution. I'm not sure I'm happy with what I heard:

Cody- "Carson, can I please get in first this time?"

Carson- "Sure, if you pay me a dollar."

At first I wondered if she even really knows what a dollar is, but then it occurred to me that I should probably be more worried that my 3 year old knows how to execute a bribe. What's next? Blackmail? Extortion?