So a doctor starts up a practice and decides to challenge himself, so he puts out a sign: "I'll cure any sickness for only $100. If I can't, I'll pay you $500!"

A lawyer sees the sign out front and decides this would be some easy fast cash so he goes in to see the doctor.

"Doctor I cant taste anything!"

Doctor says "nurse go grab vial 43!", she brings it and he puts two drops on the lawyer's tongue.

The lawyer quickly spits it out and says "UGH that's gasoline!"

Doc gets his $100.

Lawyer comes back the next day to try again, and claims he has lost his memory.

Doc says "No problem, nurse bring me vial 43!"

Lawyer says "But that's the gasoline!!".

Doc happily takes his $100, and lawyer walks out quite frustrated.

Finally on the third day the lawyer thinks he has the solution. Goes in and tells the Doc he has lost his sight.

Doc ponders a second and finally let's out a sigh. He begrudgingly walks the lawyer out to the cash register and hands him five $1 bills.

Lawyer says, "Hey wait that's only $5!"

Doc smiles and says "That'll be $100."