MARKET TYPES

DUOPOLY:

* Duopoly is a type of oligopoly where only two sellers exist in the market.
* Freedom of entry is restricted
* Nature of the product is differentiated or undifferentiated.

example:

Amazon prime and Netflix
These two are now dominant in the market , both are paid subscription services and both of them offer movies, tv series etc.

MONOPOLY:

It is a market situation where only one buyer is present.
* only one firm
* freedom of entry is restricted and completely blocked
* nature of product is unique

example:

Walmart purchases goods from china.
Here Walmart is only one buyer that purchases from china.

PERFECT COMPETITION :

A perfect competitive market is a hypothetical market where competition is at its greatest possible level.

* very many firms
* freedom of entry is unrestricted
* nature is homogeneous
* eg: cabbages, carrots etc

MONOPOLISTIC COMPETITION:

A monopolistic market is a theoretical construct in which only one company may offer products and services to the public.

* several firms 
* freedom of entry is unrestricted
* nature of product is differentiated 
* eg: Buildings, restaurants etc