If you are over 21 years old (or even better 23), have an international driver's license and 1 year or more of driving experience, you can rent a car in Vienna without a deposit.
You can rent a suitable car directly upon arrival in the city (e.g. at the airport) or in advance via an online service. A credit card is required for the rental agreement.
As a rule, car rental in Vienna (the price depends on the type of car) is provided with insurance (basic insurance contract), but in some cases the renter may require a deposit.
Are you looking for a cheap car rental in Vienna? Choose a modest compact car - you'll be charged around 25 EUR per day. Don't forget to include parking costs. If you compare renting a car with a cab, then renting a car is definitely more cost-effective, as a cab ride around the city costs an average of 30-40 EUR.
If for some reason you can't afford to rent a car in Vienna, there's an even more economical way to get around the city - a bicycle, which you can rent from one of 90 local parking lots.
You'll need to register on the Citybike website (it costs just 1 EUR) and a credit card with money (you need it to take the bike out of the box). One hour of rental is free, after that you have to pay 1 EUR for each hour. But if you put your bike down every hour (and not a minute more) and take another one, you won't have to pay at all.