I’m booked for a weekend trip to Tu(o)rin(o), Italy with some friends, and it cost a grand total of 60 euros:
38 euros round-trip for the bus between Lyon and Turin
22 euros for my half of a hotel room in the center of town
Not bad! If you’re willing to rough it a little, transport within Europe can be très budget-friendly.
If money were no object, taking the train would be my favorite way to travel. Alas, money’s often a big fat object. There are some discount card options (in France, I’m still just young enough for the Carte Jeune, which can nab you a 50% discount on your train tickets). Ouigo is also worth checking out – it’s a lower-cost train service between several major cities in France (10 euros from Lyon to Marseille, for example) – as is covoiturage.fr (also known as blablacar.fr), if you’re feeling brave. The latter is an online community board where strangers post their destination and how much money they would charge you to come along.
You can also reduce your spending with common sense and sleep deprivation, by choosing the time slots nobody wants: the earliest or latest journey, the overnight bus or train, the multi-connection flight. You can save on accommodation as well, if your flight leaves first thing in the morning. Just get to the airport late the night before and hang out there (hopefully asleep, but some people are better at sleeping under florescent lights surrounded by creeps and weirdos and the hellish repetition of intercom announcements than others). If you have an early flight you probably wouldn’t get all that much sleep in a hotel anyway, plus you’d be out the cab money you had to fork over when you realized public transport doesn’t run early enough to get you to the airport on time.