All over Greece, I saw lots of stores that sold nothing but Olympic souvenirs (and this was during the Olympic year, so although they were cute they were not cheap.)
I did manage to find a few that weren't too expensive: an Olympic photo album that costed only 10€, and a few pens that were only about 1€ each.
Other than that, don't expect to find a Tshirt for less than 28€ (which is about 35 US dollars... pretty expensive for a Tshirt!) Since the Olympics are now over, you can probably get a lot of the souvenirs for a much cheaper price than before.
What to buy: All the things you can buy in Olympic souvenirs in Athens:
What to pay: Probably not as much as I did, since i was there in an Olympic year.
Currently there are five official Olympic stores in Athens. The one is at the national airport,so it's easy to find it once you reach Athens by plane, and all the others are downtown,at the Lambropoulos shopping mall(just next to Omonia square),at Korai pedestrian street (between Stadiou and Panepistimiou streets), at Plaka along Kydathineon street and finally the largest, that opened recently, along Ermou street. Yet,you can find the official Olympic products in many tourist shops around Plaka. The prices are the same everywhere.
What to buy: You can't leave Athens without buying at least one Olympic product!
The city is plastered with Olympic memorabilia such as Tee shirts and pins and coffee mugs, etc.
Of course I bought a t-shirt, how could I resist. Very expensive, but once of a lifetime event.
I AM NOW REGISTERED as an Olympic volunteer (USA) and I will serve the visitors as being a host to the games. I can NOT wait.
Summer Olympics 2004.
What to buy: The t-shirt was maybe $30 USA dollar.
OFFICIAL 2004 OLYMPIC ITEMS...you'll find shirts, mugs, mousepads, backpacks, hats, jackets, and pins, pins, PINS!!! in both official Olympic shops and many other souvenir outlets around town. The prices are far from cheap, on the other hand the prices are government-regulated, so feel good that you will see consistency wherever you choose to buy your necessary Olympic goodies!
What to buy: Shirts are rather crazy at about 25euros a piece, but the pins were more reasonably priced at a standard 7.90euros each.