The Brethren -- Brooks Brothers -- certainly have some good suits in the $800 price range. Their 1818 line (with three distinct cuts: Madison, Fitzgerald, Regent) is in that neighborhood -- even lower during one of their fairly frequent sales. I'd suggest a visit to the Brooks Brothers store on Connecticut Avenue in DC -- very close to the Farragut North Metro stop although you can also walk easily from Dupont Circle or Farragut West. Alex and Joe in the tailored clothing department always give me outstanding service. And depending on your size, they have a fairly broad range of sizes.
Also in the same neighborhood of the city, I suggest making a trip to the second floor of the Connecticut Avenue Filene's. Many of the suits they carry there are dreck, but if you know what you're looking for you can find some very good suits as well (perhaps even a little under your price range). Look out especially for Hickey Freeman and Hart Schaffner Marx at that store. They also have Oxxford suits occasionally -- the best ready-to-wear suit in the world, arguably, but even at Filene's they're going to be in the $1100-$1200 range unfortunately.
You could also think about going over to J.Press on L Street (just a little west of Connecticut, I think the corner of 18th Street and L) and look at their offerings. They also have a made-to-order program from Southwick (not made-to-measure; made-to-order means that the suit is a standard cut in your size, made of the fabric and with the details you request) and I bet you could find some good fabrics in your price range.
Just my ten cents. And thank you for your service.
