Vienna isn't really much of a tourist trap like other cities. Prices for most museums are reasonable and student discounts are offered everywhere for those who have a student ID card. There are some precautions that should be taken like in any other big city, but in general, Vienna is very, very safe.
With a wide variety of museums, ranging from the odd (Museum of globes) to the bizarre (Museum of contraception), some of them are hit or miss, of course.
1. Horse-drawn carriages (Fiaker)
Taking a Fiaker is too expensive. Riding around town in a horse-drawn carriage sounds like fun, but when it comes to paying for it, the pleasure you had will be replaced with utter shock instantly. While these tours surely are an experience, they also will put a giant dent in your budget. Prices start from around 40 Euros for a quick tour around the downtown area that lasts about 20 minutes.
2. Avoid ticket agencies. Buy direct
Buying your tickets for cultural events at an agency means additional costs. Culture is a big deal in Vienna, you certainly shouldn't miss out on the special events here, but be smart when buying tickets for them. Try to get them without buying through a ticket office. They will charge you an additional amount of money. This is especially annoying when you could have saved those Euros by walking some additional meters.
3. Stay clear of people at Stephansplatz who are trying to sell you something or play games with you
Stehansplatz is a popular meeting point in Vienna and many people will try to make some money off those hanging around there. While there are some trying to sell you tickets to shows that might be overpriced, unexciting and of low artistic quality, these are rather harmless. Watch out for those trying to get you to participate in seemingly simple games. They work in teams and when you see somebody winning, you can assure yourself that they are part of the team.
4. Mexicoplatz and Karlsplatz may be dangerous at night
While Vienna really isn't a dangerous city, try to avoid these two locations at nighttime and act reasonably when you're there during daytime. Mexicoplatz in the 2nd district is known to be a popular place for the distribution of drugs, and the walkway below Karlsplatz is where a lot of drug addicts are spending their time. Avoid this area at nighttime when you're alone and be careful even when you're in company.
5. Disrespecting cultural events
As previously mentioned, culture is serious business in Vienna and shouldn't ever be disrespected. Try to dress and behave accordingly, regardless of the fact that you only might have paid 1,50 Euros to get in. This doesn't mean that you're expected to bring a suit and tie with you when you`re traveling through Europe, but try to wear clean, neat, ironed clothes when attending events, especially at the more prestigious places like Burgtheater, the opera, and others.