Upvote:2
https://adioso.com/ will do most of what you want. You can set departure airport to "Stockhom" and destination to "anwyhere", "internatianol" or "europe". Departure date to to a range (say Jul 14 to Jul 17) and length to "about 5 days".
You may have to play around with the dates and duration a bit to get exactly what you want. Internationally, it looks like cities like Berlin, Palma, Brussels, Copenhagen, Nice, etc. are within your price range.
For example Palma de Mallorca from Jul 15 to Jul 21 comes in at around Euro 229 per person on Expedia