Which countries have " No currency " in the world ???

  When a country don't have official currency, it does not print or manage its own money.

Instead it uses foreign currency for buying and selling things.

Reasons for a country not to have its own currency ---

1.  Countries are very small in size 

2.  Countries want a safe and stable economy.

3.  Priming own currencies is expensive.

4.  Using popular currency makes the trade easier.

Countries that don't have official currency  -----

1.  Vatican city

2.  Monaco

3.  San Marino

4.  Andorra

All these countries use Euro as their currency.

1.  Panama

2. Ecuador 

3.  El Salvador 

All these countries use US dollor as their currency.