For our transatlantic Aircanada flights in August there was 400dollars tax on top of 1000$cdnfare. That was =900€ total but still pretty good for the multi-city itinerary. To compare, Airberlin had touted "bargain" fares to New York but for August that was still coming in at over 800€ total return.
Not mentioning taxes is a problem in Europe too (Ryanair sometimes has flights advertised at 1 cent for example!),; most budget airlines only mention the taxes later in booking although the EU is also supposed to be tightening up on that. Ryanair is the worst in that you normally have an online check-in fee to add-on and always have a fee per flight per person rather than per booking fee. And a fee to check-in luggage (15kg only with Ryanair, otherwise 20kg normally). But unless you have overweight luggage they aren't going to add up to 100 extra.