Taxis can get very expensive except for shorter local fares, so using a taxi really depends on the port. For example, Barcelona is a great port for taxis since everything is relatively compact (they also have a good subway system). On the other hand, to get from Civitavecchia to Rome would cost over $100 each way in a taxi but less than $15 round trip via train. The way to save lots of money is by using public transit which includes trains, buses and the metro (subway) in Rome and Barcelona. So much depends on what you want to do during your port days. We have known some cruisers to spend more money on excursions than on their entire cruise! On the other hand, if you do things on your own you can save thousands of dollars and usually have more fun than being on a tour bus with 50 other souls. There are a few of us here that can help you with specific port questions (we have been doing indpendent travel in Europe for over 35 years) and you will also find a lot of other valuable information on the internet. We think the biggest mistake made by many fellow Americans is that they try to see too much in a port day and really do not have enough time to "smell the roses." Sitting in a perfectly located charming outdoor cafe and enjoying a drink or lunch can be more rewarding than seeing one more site. A lot of the fun can be in the planning. We have a few basic suggestions. Know your options, but do not necessarily bind yourself to a rigid schedule (be flexible). Always go to your furthest destination early in the day and work yourself back towards the port in the afternoon....which minimizes the chance of missing the ship. Its also good to know what you would do if you did miss the ship (I can help you with this) although that is very unlikely to happen. We have been cruising (and also driving) in Europe for a long time and have never missed a ship (came very close twice). When I get some time I might actually write a detailed post on how to plan to "miss the ship" since that is something that scares so many cruisers from doing anything on their own.