As an undergrad traveling around Europe, I didn't have a lot of money to spend on souvenirs, but I still wanted a memento from every city and town that I visited. Though I couldn't afford, say, a miniature plastic Eiffel Tower, I did stumble upon the perfect souvenir for anyone looking to save money: transit maps and tickets.

By keeping tickets, I not only had a physical keepsake of my trip, but I also had a great way of documenting exactly what I did and when. And by keeping maps, I could literally retrace my steps at any time.