It would be nice if people asking questions contributed something. However, Greece (Athens, Crete, Thessaloniki) is pretty cheap. Not £2.50 at anywhere you are likely to find on your first visit, but a 10 euro suck and fuck is easy to find (see UKP Wiki) or 20 Euro in slightly better buildings, scruffier area. There are also better quality options, but if you have to ask about the basic then you might be better sticking to them.
I'm happy to post more info if you contribute with some reports about your punting elsewhere in the normal way. Regards.