Re: Eating, reasonably, in DC
I actually just had dinner in DC at a very reasonable place on Sunday night: Stoney's, at 1433 P Street near Logan Circle. I can't seem to find a web site for it, but if you google it you'll see some reviews/info. It's a casual bar/grill type place, and just about everything on the menu costs less than $10. Our group of five ordered a pizza (reportedly very good, though I didn't try it), a few Greek salads (nothing special, but good) and a crabcake sandwich (ditto). I've heard that the burgers and grilled cheese are well worth trying too!
As for finding other affordable places, get a good guidebook and check out the options at the cheap end of their listings, or go online and do a search for Washington DC dining -- in many cases you can go onto dining sites and filter your search results by price.
Good luck. Hope that helps!
"I haven't been everywhere yet, but it's on my list." -- Susan Sontag