@dave415
I assume you're not asking about San Francisco, so it would be useful if you updated your location or at least said in your post what Munich neighbourhoods you're interested in.
As mentioned above, many restaurants have daily lunchtime specials for around €5; the best one that I know of is
Schwabinger Wassermann.
Many places (Bavarian or otherwise) have €5.55 or €6.66 menus at lunchtime:
Sendlinger Augustiner, for example, has them on weekdays (they include soup or salad, main dish and coffee or dessert); the same restaurant has a "Schnitzeltag" on Saturdays, when the different kinds of schnitzel (Wienerschnitzel with potato salad, schnitzel in mushroom sauce, and so on) all cost €6.66. I'm sure lots of other restaurants offer similar deals.