Washington DC and its Maryland and Virginia suburbs have plentiful dining options in all budget ranges. While there are plenty of high profile and pricey restaurants in the Washington DC area, you will have no trouble finding budget places that offer excellent food from around the world. Here are just a few of the hightlights.
Julia's Empanadas takes the cake, so to speak (or is that the empanada?) when it comes to yummy but cheap food in Washington DC. With multiple locations around the city, Julia's offers a range of flavors of that tasty Latin American staple, the empanada. They come in both sweet and savory options, and my favorites have to be the "Jamaican curry" and the "turkey with spring onions" varieties for the savory ones, and the sweet almond paste filled one among the sweet choices. A combo empanada meal consisting of a savory and a sweet empanada and a fountain drink will set you back just about $6.00!
The next option might not strictly qualify as budget, but a very good value nonetheless. It's Teaism, a Japanese "inspired" teahouse with locations near Dupont Circle and Penn Quarter, which has an ecletic menu with innovative takes on Asian dishes, and a wide selection of teas, as you would expect from the name. Dishes are very reasonably priced, with many entrees coming in at under $10 or just a bit more. The nice ambience and food quality are very good for that price (or any price for that matter).
Within Washington DC itself, quality budget joints are somewhat difficult to find, but such places abound in the suburbs. This is especially true if you visit some of the ethnic restaurants that are scattered across nondescript shopping malls. If you are a fan of Indian food, you could visit Food Factory off Route 1 in College Park, Maryland. Tiffin in Langley Park Maryland is another good Indian option. For cheap and good Vietnamese food, visit the Four Corners shopping center in suburban Virginia. If you are craving good Chinese food, Chinatown in DC is not the place to go. The Washington DC Chinatown is unfortunately now run over by generic shopping centers and chain restaurants, so for inexpensive and really good Chinese food you might consider going up to Rockville and Gaithersburg. Michael's Noodles in Shady Grove and Chopstix in the same general area are excellent Chinese restaurtant choices in suburban Maryland.
There are so many other cheap and good restaurant options in Washington DC, but the above are a sampler. So go forth, explore, and bon appetit!