Stockholm on a budget

[schnapperin]

Hi,
since I´m having a few days off in Mid September I decided to use the lovely offer from Ryanair and will be heading to Stockholm for three days - my first time to scandinavia ever!

Now I´m looking for some nice spots for lunch/dinner and lovely cafes for a traveller on more a budget (25 € for dinner for one - no alcohol), which shouldn´t be Thai or italian, as of course those are restaurants I could visit at home aswell - it should be typical swedish or nordic.

And is it worth to book a table for the smorgasbord at the Grand Hotel?

Thanks