The cheapest lower level tickets for a Ravens game are typically found in endzone Sections 111-115 and 138-142. These large, shallow sections are located below each of the large videoscreens, yielding them head-on views of replays and scoreboard entertainment.
So while the views of the videoscreen are ideal, views of the action on the field are less superb. The low-rising rows makes it easy to walk up and down the stairs, but also makes it a challenge to find seats with enough elevation to see the entire field. Your best bet is to sit in the highest possible row so that you're high enough to see the other end of the field clearly. Unfortunately, this comes with the downfalls of having to walk up the stairs to your seats and being even further away from the field.
If you don't mind sitting in the upper deck, you can find better views of the field in the front rows of the 500 level. But if you just want to get as close to the field as possible, choose low rows in Sections 109 and 115 where you'll be right next to the players as they come onto the field.
See the Ravens in the tunnel, feel the heat from the flames, yell at opposing team as the enter the tunnel at halftime and end of game. The best!!!