Not the cheapest of places but Copenhagen is a beautiful city with lots of green spaces, cycleways and Christmas markets dotted around town. Bars below are cheap and some are “brown” bars.
There is a train station at the airport and frequent trains into town which is a 15 or 20 minute ride.
Take a ferry ride to see Copenhagen from water. Much cheaper than tour boat
Mikeillor bar with lots of real ales
Dubliner for sitting outside
City centre bars traditional allow smoking but atmosphere and prices good
Student house has happy hour till 8
Italian la perla is cheap
Persian Zafran is bring your own bottle
Kebabish is good but not swanky
Dalle Valle place excellent and half price drinks and good in uni area.
Areas to visit with street food in order are
Paper Island at end of Nyhaven
Meat packing district
You must hire a bike as cycling is brilliant
Go to seaside town by bike
Dyrehaven has wild deer