Just point to the best-looking pizza and tell them how much you want. Two hundred grams is a meal. They heat it, you eat it. If school is in session, drop by the cafeteria of any European university. It's a surefire way to meet young locals with open and stimulating minds.
Students are often anxious to practice their English with a foreign friend.
This is especially handy as you travel beyond Europe. In France, many cafes offer fixed-price meals such as a plat du jour or menu touristique. You'll get your choice of an appetizer, entre, and dessert at a set price. Eat hearty in Scandinavia, Europe's most expensive corner. Keep your eyes peeled for daily lunch specials called dagens ratt.