Can we say (un peu d’argent) ? And will it make a difference in meaning form ( peu d’argent)

Hi Nabeel,

yes, there's a slight difference in meaning.

un peu d'argent -- a bit of money.
peu d'argent -- little money.

For example:

Il ne me faut qu'un peu d'argent pour ça. -- I only need a little bit of money for that.
Il est pauvre. Il a peu d'argent. -- He is poor. He is little money.

Hope that helps, -- Chris (not a native speaker).