Let me make a quick calculation.
The return tickets with Ryanair (budget airline) for both of us was around $250, I think.
Staying in hostels $200.
Eating and traveling is around another $250.
$700 is possible. We didn't fly in Florence as well. We flew into Pisa which saved us quite some money. :)
oh that makes sense. We do not have Ryan Air in my country. One way ticket for us is not less than $300.
I hoped you enjoyed. Italy is really really beautiful.