Set your budget. Divide the money you can spend on food by the number of days you plan to stay in Europe, and you will know how much you can spend each day. If you go over your budget, be sure to spend less on food the next day, so you don't run out of money before your trip is over.
Stay with a kitchen. Many youth hostels and hotels in Europe have shared or private kitchens. Some hotels even have kitchenettes with a refrigerator and stove in your room. You can save a lot of money by buying a few groceries and cooking them yourself instead of eating out.
Shop the farmer's market. Like in America, many European towns have weekly or more frequent farmer's markets. These local vendors are a great source of fresh fruits and vegetables.
Eat on the street. Some of the best local food comes from street vendors, and you can often eat more and spend less than you would in a restaurant. Street vendors are also a great way to sample truly local cuisine. Icelandic hot dogs, Parisian crepes, Italian pizza and German bratwurst are some examples of common street foods.
When eating out, order tap water. If you order water in a European restaurant, they will bring you bottled water and charge you for it. However, tap water is safe to drink in Europe and it's free. Learn how to ask for tap water in the local language.
Order the house wine or beer. As in America, this will often be the least expensive option for alcoholic beverages, and it's another opportunity to (literally) taste the local culture.
Eat at cafes and bakeries. If you need a midday snack to keep you on your feet for a few more hours of sightseeing, try grabbing a pastry or roll and a coffee from the nearest bakery. In countries like Germany and France, which are especially known for their pastries, you won't spend too much and you will get to sample the local culture.
Go off the beaten path. Bigger cities in Europe tend to be more expensive overall than smaller towns. Find some obscure towns to visit along with the major tourist sites.
Eat where the locals eat. Don't be afraid to try to speak the language, even if you only know a few phrases! Most people are friendly and will be happy to help you. Try to make friends and ask them where you can get the best food for the lowest price.