The best way to undergo a Hypnosis session is always the one where a trained instructor induces the trance in person. However, there are instances where this personal guided trance may not be convenient. Whereas the time constraint and availability of renowned expert are the main reasons for people to adopt to self hypnosis; with many there could be reasons like not being comfortable to open up before the expert or feeling ashamed of disclosing their weakness.

When a person induces hypnotic trance without guiding suggestions from an expert in person, it is called Self Hypnosis.
In stead of personal instructor, the hypnosis instructions are pre-recorded on an audio device and the person can undertake the session by following the instructions played on the device. 

Such pre-recorded tapes or audio CDs are easily available in the market through which anyone can learn and undertake self hypnosis. This is an easy aid to people who are trying to lose weight or quiting a bad habit like smoking. People who have no such issue may also use such self hypnosis tools and enjoy relaxation and keep their mind clutter free. 

There are businessmen and executives like market reprepresentatives who regularly use self hypnosis not only to counter the stress but also to get self motivation to better their performance and taking up constant challenge of outscoring their own targets.  

Self Hypnosis and motivation material by Brian Tracy, Joe Gerard, Napoleon Hill, or Kim Klaver are quite popular.