1. Figure out your transportation situation
Fionn and I are healthy people in our 20s, so we do a lot of walking. We usually only take public transport if we can't walk it ourselves. This requires some planning to figure out the most cost effective option; day pass, single ticket, weekend pass, etc? In Barcelona, Berlin, and Rome we used the heck out of our day passes, but in places like Luxembourg and Riga we never set foot on public transport.
Public transportation is almost always cheaper than taxis, but if you're planning on staying somewhere remote or staying out late, you might need to factor that cost in!
2. Keep food costs down
Eating out is expensive! This is probably one of our biggest expenditures when we travel, so we try to be creative with our meal planning.
When we're traveling to our destination, I always try to pack us snacks so we won't succumb to a 12€ soggy airport sandwich. I also toss in granola bars or power bars in my purse to use during our trip so we can stave off hunger pains while we're sightseeing. Hunger can make you agree to some not so ideal lunch options and makes everybody snappy.
For breakfast, I try to book hotels with breakfast included or we scope out the neighborhood for bakeries where we can grab a coffee and a pastry.
We usually decide to splurge on lunch or dinner, but not both. It's usually pretty easy to find a quick bite for lunch (sandwich, pizza, kebab, street food). We've also visited markets or grocery stores for a quick picnic style meal. These have worked great for lunch and dinner-in Rome we brought our grocery store purchases back to the hotel and had a picnic in our room. That was one of our favorite travel dinners!
Again, it helps to do some research. Check out restaurants in the area of your hotel or a landmark you're visiting, and check out what the area is famous for. You might find an awesome local paella place for a steal!
Finally, budget some money in for snack. I have a sweet tooth and around 3 or 4 pm I always feel like stopping for a cup of tea and a piece of cake or a pastry. Not to mention, if we pass a bakery I usually have to stop and try something! That's the fun of new places!
3. Decide which attractions are worth seeing.
Attraction fees can really add up, so our general rule is we won't pay more than 5 euro a person unless it's REALLY worth it (Sagrada Familia, Colosseum, etc.-totally worth breaking that rule). Needless to say, if it's free, we'll probably visit it. ;)
Castles and museums can be fun and educational, but again take it on a case by case basis. Fionn and I have serious "castle fatigue" after a few years in Europe, but we're always up for a good history museum!
Attractions are fun, but tourism is a business, which means lots of people charge a fee to visit a "tourist attraction" that ends up being pretty lame. You don't have to hit every single box in the tourist guide. Sometimes the most fun we have in a city is just walking around, getting lost, and stopping for a coffee and a pastry in the park. Totally free (well, except for the coffee!) and totally memorable.
Ephesus: totally worth the entry fee!
4. Look for deals
If you have a student ID or are an EU citizen under 26, use it to your advantage! Many attractions in Europe will give you free or reduced entry. If you have an EU student card (as a study abroad student) just show that and sometimes they'll give the discount even if you aren't a European.
Being under 26 entitles you to discounts including trains and public transport. Just ask!
When it comes to trains, there are almost always deals to be had. Germany has the Schönes-Wochenende-Ticket (allowing groups of 5 to travel cheaply on regional trains on weekends) and federal state specific tickets like the Bayern Ticket or Brandenburg Ticket, which allow people to travel within a specific federal state on the regional trains for a flat rate. They're a really great deal, even if it means the trains are a little slower!
In Spain, train tickets can be bought cheaply in advance using the online discount, and it some cases you can get a deal on 4 seats surrounding a table (Mesa seats). Fionn and I bought the 4 Mesa seats for less than the cost of 2 regular seats.
5. Remember you don't have to spend money to have fun.
Shakespeare and Co in Paris. I could spend hours here!
Walking around, shopping, finding a quiet cafe or park and people watching-these have been some of our best travel memories. :) All free!