Dinner or Lunch for 2 in Baltimore under $25.
SoBo Cafe, all lunch sandwiches are $6, and are quite filling and yummy. Dinner during the week has specials, especially Monday- $10 steak night.
Samos in Greektown, you can't beat the prices (or the food), and is BYOB.
Captain Larry's has specials every weeknight also, check their website- www.captainlarrys.com. Better than average barfood in ultra laid-back setting.
Wine Market- Mondays all entrees are 20% off, and wines 15% off.
those are my go-tos for cheap eats.