The strong presence of large immigrant communities, plus a new cosmopolitan outlook on food, means that Germany offers an increasingly eclectic mix of restaurants and cuisines, catering for all palates and wallets. From haute cuisine to fast food joints, you won't have a problem finding a great place to eat within your budget.
For a traditional atmosphere and healthy portions of home cooked meals, das Gasthaus or der Gasthof, an inn or tavern, may be just the ticket. These are generally informal places where you can expect a strong emphasis on regional specialities and dishes.
Another option is die Bierstube. This is basically a pub that also offers a fairly limited food menu. Die Bierstube is generally smaller than der Biergarten, a beer garden, where you can usually eat and drink outside in a fun and relaxed environment. Alternatively, you can try der Ratskeller, a restaurant in the cellar of an historic building. The food is often of a very high standard to match the impressive surroundings.
There are also cafés where you'll be able to get coffee, pastries and other snacks and drinks. Cafés tend to get very full between 4pm and 5pm in the afternoon when many people are enjoying their afternoon Kaffee und Kuchen, coffee and cake. For sweet goods, you could also try die Konditorei. Although this translates as confectioner's shop, you can buy a full range of Germany's famous pastries here too. Finally, for sausages and meat snacks like Bratwurst, fried sausage, you'll find a good selection at most Schnellimbiss, takeaway food stalls, which are dotted around major towns.
When entering a smaller style restaurant, customers are expected to find their own seat, often sharing a table with other diners. One phrase that will therefore come in very handy is Ist dieser Platz frei? Is this place free?