Fraud in the inducement is also another one that is fairly common yet not known all that well. That fraud simply involves someone promising a condition that causes the other party to enter into an arrangement only to discover later the promise was groundless. It must be shown that, absent that promise or condition, the complaining party would never have entered into the agreement.
Here's how that works. Let's say Bob sees Joe the Dentist to have some work done. Joe the Dentist says Bob needs an expensive procedure. Bob says he can't afford the procedure, so Joe says insurance might cover it. Joe claims to check with Bob's insurance company and tells Bob that the procedure will be covered. Bob tells Joe to go ahead and perform the procedure.
Bob later gets a Bill for $8,000 as his insurance company didn't cover the procedure. In that case, Bob may be able to argue fraud in the inducement -- he would have never had the procedure done without assurances from Joe that it would be paid for by insurance.
Believe it or not, this kind of thing goes on regularly. Most people in Bob's position would pay Joe's bill and chalk it up to experience rather than how "fraud in the inducement" and refuse to pay. Fraud in the inducement, by the way, is a great defense to raise in collection cases if it is available.