Despite the many technological gadgets on new cars these days, it is still possible to lock the keys in a rental car in Europe. If that happens to you, phone the rental company's 24-hour road service, or call a locksmith. Do not do what Sam (not his real name) did recently in Oslo, Norway, when he discovered the keys locked inside his midsize station wagon. To retrieve the keys, Sam decided to break one of the car's side windows. His way of dealing with the problem was a quick and relatively easy solution, but shockingly expensive. Things are expensive in Norway (an intermediate sedan at the Oslo Airport is about $670 vs $240 for a similar vehicle at the Frankfurt Airport) but Sam never dreamed the bill for a broken window would come to a whopping $3,500. At this point we haven't seen the damage documents from the rental company so we don't know if there was more involved than just replacing the window.