Hi farhan,
first of all, i would like to congratulate you on your scholarship. It seems like a really good deal since they are paying you all the costs for your accommodation and a part of your tuition fees. Strange though, because i had no idea Greek Universities charge tuition fees. Maybe for the ones outside the EU.
I wouldn't say that life in Athens is particularly expensive comparing with other big capitals of Europe(and not only), such as London, Paris, Amsterda, Rome, etc.
However, it has been a very long time since i left Greece but when i left Greece it was before crisis and still the prices were not so high. I still have friends in Athens and as far as i know the rents are pretty low this period and i am sure that you can find some very good deals in restaurants and eating places as well.
Now, depending in which area of Athens are you going to go out, Athens is a big city and many places to go out for a drink, you should expect to pay different prices for a beer or a drink.
In general you should expect to pay an alcoholic drink in a bar or cafe at about 7-8 euros and a coffee (again depending where are you going to have a coffee) at about 3-5 euros. I know it sounds expensive but with this price comes a lot more than in other countries they don't offer.
If you choose to go out in areas where many students and youth are going (exarhia, psirri and others) the prices will be lower. If you choose more fancy areas (kolonaki, falhro and others) expect that you are going to pay higher.
As for the clubs....well i am not really sure since i was not very fond of going out in a club but you should expect to pay a ticket at the entrance (which also gives you a drink) at a price of about 15euros and then each drink you'll get will be around 8 euros.
Transportation. The tickets have been considerably up during the crisis unfortunately and now a ticket for all the transportations (metro, subway, buses, trams) for 90 mins cost 1.40 but with a student discount cost 0.70 euros. A monthly pass for all the transportation means cost 45 euros and with a discount cost 23 euros. Not bad actually.
The supermarket's costs. Comparing with other big European cities many argue that Greek prices are higher. Can't say really but still is not so cheap. It always depends of course of what you are buying and how much you are buying. There is, however, usually twice a week in each area of Athens and open market where you can find vegetables, fruits, fish, clothes, and many other things much cheaper than supermarkets and shops.
You should also expect that you will handle most of (if not all) your transactions in cash.
Now the the question of how people are in Greece. I am sure that you have heard so many things about how friendly Greeks are and about their so-called Hospitality.
It is true in general and in some ways. The people on the street are usually rude (common characteristic of the southerns in Europe) but once you get to know them and know you they get very open hearted and hospitable.
I must say though, with huge disappointment and frustration that the Greek society has changed dramatically during the crisis and there is a lot of racial prejudism, stereotyping, racism and acts of violent toward foreigners. Particularly the ones who have a darker skin. There are hundreds of thousands of undocumented immigrants on the streets of Athens from Afghanistan, Pakistan, Iraq and elsewhere that have been targeted by neo-nazi and fascist groups.
Greeks in general speak English quite well (the youngsters) but also the old people speak English enough to give you directions or assist you with something. I must, however, point out that if someone look more middle-eastern or Pakistani or black will be most of the times classified as an undocumented immigrant and thus will be insulted, neglected and will be refused assistance.
It is so frustrating at least to see a society behaving like this. It makes me angry.
If you decide to go to Athens i would strongly suggest to find accommodation outside the center of Athens (omonoia, kato patissia, attiki, monastiraki, patissia, victoria) and keep you documents, visas, student card always on you.
I hope the info i gave you where somehow helpful, if you need further information about something in general or more specific please let me know.
Cheers,