The handpainted wooden ceiling in the thrift shop is worth the stop, but the goods on offer here range from big name Scandinavian design to nautical oil paintings by forgotten no-name artists. There's also a broad range of prices--if I had had more than a backpack and lots of travel left to go, I would have picked up a serving platter or a lamp at unbelievable prices. In the end, all I took away was a little antique plate for about 4 dollars.
At the warm, wood floored cafeteria, plan to share a table with a mixture of Swedish businesspeople, young hipsters, and the (very) occasional tourist. The 75-kr daily special served here (which includes salad, a main dish, and coffee) would be a steal at twice the price. Plus, both lunch and shopping benefit Stockholm's poor.
The Stadsmission also happens to be just across the square from the Nobel Museum. If I had a few hours to spend, I would lunch in the Stadsmission cafeteria, wander through the Nobel Museum and marvel at the rotating display of laureate photos, treat myself to Nobel ice cream at the restaurant there, complete with chocolate Nobel Prize replication (don't forget to look under your seat--it's signed by one of the Nobel prize winners), and then stop into Stadmission's Butik second hand shop. A wonderful way to spend the day--and surprisingly cheaply by Stockholm standards.