The best payout is still clinical trials if you are willing to be a lab rat. They pay 4 digits for investigational medicine and require you to stay-in for observation which will feel like confinement back in NS days but with the freedom to surf net, watch tv and make phone calls.

High risk = high payout. Ask yourself if you are willing to be a rat lab for an experimental drug for HIV. Think of that before you think of the money.