Every time I'm at Insadong, I go to the Ssamzie-gil building to buy my favorite traditional Korean snack. It's a bag of peanut/puffed rice snack bars that are made with healthy ingredients, such as fruit syrup, instead of regular refined white sugar.
These are so addictive, if there's no one to stop me, I will finish the huge bag in only two or three sittings! No joke. I have tried their other snacks, which are also good in their own right, but in my opinion, they don't hold a candle to the peanut bars. These bars aren't overly sweet or sticky, and they have the perfect ratio of peanuts to puffed rice. And the raisins and orange zest just take them to a whole other level of awesomeness.
Here are some of the other snacks they have:
The two ajushi's that run the stall are also really chill and friendly~ And they always put out generous amounts of samples for tourists to taste. :) Go to their website to learn more about their snack company!
To find them, just go to the Ssamzie building. They're located on the first floor open square.