Next  to the Stoa of Attalos in the Ancient Agora there is Monastiraki, the flea market. Whatever floats your boat.

Walking West from Monastiraki the flea market and the Ancient Agora you get to the Roman Agora. Obviously this has been an area of relentless buying, selling and philosophising. It still is. There are very ancient ghosts hovering around over here. 

Below the ancient ghosts, swarms of tourists are pushing their way through the narrow streets

View of the Acropolis from the Roman Agora

And finally you get to Plaka, the Old City. Lots of little shops, bars and restaurants