Why does the flower girl talk to the military looking gentleman? What does their short conversation tell you about the flower girl? How much does one bunch of flowers cost? How much does he offer her? (Act 1)

Eliza wishes to sell the man a flower. He offers her three hapence.

THE GENTLEMAN. Now don't be troublesome: there's a good girl. [Trying his pockets] I really haven't any change—Stop: here's three hapence, if that's any use to you [he retreats to the other pillar].