If you are, like me, a regular reader of The Guardian, and thus are aware of their podcast on mini-breaks in Stockholm, then you'll want to check out this other website, offering information on Cheap Hotels in Stockholm .
Getting there is no problem and the place itself is gorgeous, especially in the summer. The islands, a vertiable archipelago in fact, just outside, rather make the pace. There's also the rather interesting sight of the rather shapely natives disporting themselves in the sunshie.
However, the place is expensive. £ 6 or £ 7 for a beer is not unusual, and it's not any cheaper from an off licence either. So you will want to try and save as much money as you can by geting a cheap hotel in Stockholm.
On other very strange tip for saving money in Sweden. All the off licences are state owned. They charge exactly the same margin on all products. So while alcohol is indeed very expensive, they're oddly, a very good place to buy fine wines. Not only is the chain the largest purchaser of wine in the world, because of the low margins, it's often cheaper to buy the really good wines than it is at home.