If you look for a Polish meal for lunch or a dinner (depends on what time you eat your meals) you may want to eat some Pierogi (word is already in plural, so please try not add "es" on the end :P )
There are many places you can eat these in Krakow in many different flavours.
This plate of crubled meat filling pierogi was ordered in: Pierogarnia Krakowiacy on Szewska street.
Price... not bad (5.90 PLN/1 pierog) with current prices of ingredients, but when someone offer you 1 pierog for more than 10 PLN without oven baking it... then you might want to reconsider.