The town of Varkiza has a few small free beaches and a large public pay beach and the sea is pretty clean here. There are lots of restaurants, cafes, shops, in fact it is almost like a city that comes right down to the coast. You can catch the E22 from Ellinikon Metro Station. The Orange KTEL from Pedion Areos also stops here and you can pick that up in Syntagma Square. The tickets for the pay beach are about 8 euros, much more reasonable than Astir, and children under 6 are free. A taxi here will cost about 15 or 20 euros.