I think public transport is the better way the using a taxi. there is a 24h service, underground from 5.00 a.m to 0.30, during the night there is a good night bus service use taxi only for short distances, a trip form the centre to "schloss schönbrunn" will make up to 15 euro, underground would be 1,5 euro and is faster.

Tickets for visitors to Vienna "Einzelfahrschein": € 1.50 in the Vienna Transport Authority´s ticket offices, ticket machines (underground ) € 2.00 in the means of transport The ticket for a single trip can be used for any single trip within vienna. You may change lines, but you may not interrupt your journey. "24 Stunden Wien" € 5.00 in the Vienna Transport Authority´s ticket offices, tabacconists, ticket machines The 24-hour Vienna card is valid throughout Vienna for exactly 24 hours from the time they are punched. "vienna card": € 16.90 in the Vienna Transport Authority´s ticket offices, hotels The Vienna Card is the ideal "entrance ticket" to the city: a 72-hour rover ticket valid on the underground, on trams and buses, with additional discounts and benefits. Punch it once and enjoy all the benefits. Comes with a comprehensive information brochure. "72 Stunden Wien": € 12.00 in the Vienna Transport Authority´s ticket offices, tabacconists, ticket machines The 72-hour Vienna card is valid throughout Vienna for exactly 72 hours from the time they are punched. "8 Tage Karte": € 24.00 in the Vienna Transport Authority´s ticket offices, tabacconists, ticket machines The 8-daycard is valid for any eight days, not necessarily eight consecutive days. It is a rover ticket, which means you can travel all around Vienna. You can also use the ticket for several people travelling together: simply punch one strip for each person in the group. How to punch your ticket Tickets bought in advance must be punched in a blue ticket cancelling machine in the tram or bus or at the barrier before you board the underground train. Free travel for children Children under age of six travel free on Vienna´s public transport network. Children under the age of fifteen travel free on Sundays, public holidays and during Vienna school holidays.

Budapest is really near to Wien, a good way to go there is to take the Ausflugskarte at the Westbanhof train station. It will cost less than 40 Euro and it includes a two-way ticket to Budapest and tram tickets for this wonderful city (during 4 days).

Vienna offers a good way of getting around town, with a choice of tickets valid for 24 hrs (60 S) or 72 hrs (150 S). They cover just about every public means of transport (tram, underground, bus), but are not valid after 22H !!! A single journey costs 10 S

The cheapest way of travelling in Vienna probably is the "Umweltstreifenkarte" (environmental ticket), which provides you with eight strips, each valid for one person and one entire day (not valid on night buses) for ATS300.-- Never forget to validate the according number of strips before getting on the subway!