Vaya una cuadra. What's the difference betwen vaya and Voy ??

What's the difference between Vaya and Voy?

Do they carry the same meaning?

Could anyone explain the use of these two words?

Hola Fiona,

Voy is "I go" or "I am going", depending on the context. of the verb ir .Vaya can be  the formal command or the present tense of the subjunctive of ir for the first person, or the second person, using the formal.

Saludos,
Ricardo

Here are a few examples of what Ricardo was explaining:
- Que le vaya bien.  May it go well for you.
- ¡Vaya ya! Go already!
- Voy a la tienda I'm going to the store

Vaya can also be used as an exclamation 
- ¡Vaya, ya he suspendido otra vez!
 

Vaya is a formal/polite command .
Por ejemplo: Vaya a la tienda- Go to the store(as a command)
Voy - I go
por ejemplo: voy a la tienda- I am going to the store.