First of all, I proudly announce you I've been to Vienna with 100 Euros!
Well, thanks to Skyeurope and a ticket reserved two months in advance, I made it at 30 Euros, place included.
Lodged, then, in the fresh Meininger hotel, opened in the Columbusgasse, 30 meters away from the Kepler metro station.(U3) Brand new, as I said, IKEA furnished, with an all-you-can-take breakfast (1ox for the lovely brown buns!) plus 10 minutes free internet for everybody in the room, if the reservation is made online.
What other expenses you should keep in mind: the CAT - train that takes you from the airport downtown...9 Euros/person. BUT! If you go with friends and you are 3, I suggest you reserve a cab, online of course, here. The price from the hotel I was lodged in to the airport was 25, 5 Euros, so less than 9 euro/person, if you are three. I had to take it in the morning, since my plane was leaving at 6 AM, I made the reservation in time, a month before, and with no other phone call or email, ten minutes than the hour I was expecting the cab, the driver was there, waiting. For going around in the city, the 72 stunde (72 hours) ticket is the best, at 13, 60 Euros. It works on all buses, trams and underground trains, for 72 hours, as it is called.
Places to eat: accidentally we've had our first meal at Cafe Diglas, which proved to be in our guide, so our 6'th sense is still working.
*The menus were numbered, so the waiters dropped at our tiny marble table saying 1, 4, or 5 :).
The last day we dropped again at the Diglas, since it is very closed to the Stephan's Dome, for an apfel strudel. Very good, as we guessed watching on a wall screens how the people make it.