Come on now.......Are you trying to tell me that you can not get a decent meal for 50 zloty? Ok, for Krakow here are two examples of good restaurants with decent prices.
Well, tak, JR. Typical menu when taking one's spouse or significant other would come to well over 50zl unless exercising very obvious budgetary restraint and you'd need some excuses, such as
"Soup shmoop. If you've tasted one you've tasted them all. Let's go straight to the main course."
"No, no, a starter would just fill us up and spoil the main course, darling!"
"No dear, I heard the [insert name of dish] isn't too good here, try the [insert name] it's cheaper I mean much nicer."
"Dessert? We can share!"
"Coffee - who needs it?! Plenty at home! Tap water will do? ...What, tap water's not available?!"
In central Warsaw you can get far more food than you can eat for 20zl but you wouldn't call it 'going out for dinner'.
I get the feeling that the OP was talking about something closer to that than eating glonka in a brew-pub.
Exactly what I want to say - nail hit.