There are single tickets, short-term passes (24, 48, 72 hour pass), weekly passes, monthly passes and annual passes.

A short-term pass is good for unlimited travel by tram, bus and rail, night bus inside Vienna’s Zone 100 for as long as the ticket is valid. Prior to use, you must validate your pass by punching it in a ticket validating machine (conveniently located in underground stations and on buses and trams).

A short-term pass is transferable but may only be used by one passenger at a time.

Prices: http://www.wienerlinien.at