I can give quite a lot of information here. Part of this depends on your definition of 'reasonably priced'. Bear in mind that Washington, D.C. is a high cost of living area and unless you live somewhere like New York or Alaska, you will get sticker shock on everything.
Here, though, are my personal recommendations:
Ray's. Ray's operates four restaurants - two Ray's The Steaks, one Ray's The Nets (Seafood) and one Ray's Hell Burger. The primary Ray's The Steaks location is at 2301 Clarendon Boulevard. It is in the Navy League building. It is the cheapest steakhouse in D.C. In my opinion, it is also the best steakhouse in D.C. You can pay a LOT for a good steak here. There is a second location in southeast which has a more southern feel (Grits as a side, etc). I haven't been to Ray's The Nets as my husband hates fish, but have heard good things about it. Ray's Hell Burger was started as a way to use the parts of the cow that don't make good steaks - so you turn them into burgers. Huge burgers at a low price, although the downside is the location is not metro accessible - you have to take a bus.
My second suggestion is Hard Times Cafe, a local mini-chain that has several locations. It's a chili house. Don't buy anything but chili. If you don't eat meat, buy the vegetarian chili. (Even if you do eat meat, consider the vegetarian chili). Oh, and they have fantastic root beer.