First, get your mind out of the gutter. This is a different kind of poke.
There are many centers across the country that will pay you for plasma. But you'll have to endure a poke in the arm, which some people can't stand.
In most cases, you can go in twice a week and sometimes can get between $60-$80 a week. This may not sound like much, but an extra $240 a month can be the difference between a repo man and getting current with a vehicle payment.