The beer is super expensive at Stockholm-Arlanda Airport, usually around 100-120:- (10-12€) for a 50 cl lager at any bar or restaurant. As a Swede I find this outrageous as a beer in the alco shop is 10:- (1€).
The airport actually has had a page listing cheap foods, but the drinks are still expensive at these places.
Is there any place at Arlanda with cheap beer?
Because of Swedish laws you are not permitted to drink your own alcohol at the airport.
Frequent travellers of Arlanda Airport, as well as airport staff, all know the cheapest beer at Arlanda can be found at McDonald's in Skycity.
One large beer at McDonald's is 65:- (5.5€).
McDonald's and Skycity can be found in the departures area, before security, between terminal 4 and 5, it's a quick walk from all terminals. If you're in terminal 2 you can take the Arlanda Express for free between the south and north station.
Why is this special? It's the only McDonald's in Sweden with right to sell alcohol.
Keep in mind that it can take 25 minutes to pass the security and get to the gate and that the gates usually close 30 minutes before the departure time, so leave at least 1 hour before departure.