Copenhagen is the capital of Denmark
Public transport is open (with no gates like in Berlin, Prague, etc) and very easily blackrideable. The tickets are definitely expensive and expires in a certain period of time once issued by the machine (no need to validate them). Copenhagen's public transportation system is one of Europe's easiest to use for free. All the S-Trains and Metros can be entered without having to cross any gates, the only thing to watch out for are ticket inspectors. Those usually wear a uniform on the Metro and sometimes do on S-Trains. Chances are not very high that they'll show up, but they exist. When you see them, just run away from them and leave the train asap, pretending not to understand etc. Although they do, they are legally not allowed to hold you, but they can block your path. If they can't check whether the address you're telling them is correct or if you're a foreigner (and not really under an obligation to pay any fines anyway), they might try to take the money you have with you, so better (pretend to) not have money for paying this. [i had to pay 700 dkk -hf]. Using public transportation is, by the way, an excellent way to get through Copenhagen if you're traveling between Sweden and the South/West.
Check rejseplanen for timetables of buses
Accommodation & Wild Camping
Lots of people hosting even more looking for host..you can find one but you can also not finding him/her..
Lockers can be found for daytime activities at both the National Museum (closes 17:00) and The Satents Museum for Kunst, (Closes 20:00.) Lockers cost 10dkk which is refunded upon return.
If it's cold/rainy outside you can try sleeping on the 3rd floor of Field's mall, on the bottom of the exhibition area where the lift leaves you facing, just in front of Ørestad metro/train stop. --Sevetse -slept there on a Friday night and no one ever came to disturb, not even for cleaning (which they might do sometimes). There is free wifi and toilets open all night long. Sevetse slept on big cushions available at the time. -tried to sleep there this night (2017-06-26) but about midnight came security guy and told her that she cant sleep there. But there is option to take train (tog) next to the Field's mall, under metro, to airport (just 2 stops) and sleep there. Just be sure to wake up before 6-7a.m. because if you oversleep security would wake you up and will ask you to show your plane ticket.
There are spots where you can camp, just ask around.
Naturcenter Vestamager: Granatvej 3-15, 2770 Kastrup. There's a metro stop close by, on the M1 line, called Vestamager. It has water, toilets, you can make a bonfire, etc. It's a proper free of charge camping site, for more info check here. Update: DO NOT go to Naturcenter Vestamager at Granatvej. Instead, check this map for some spots with 4 shelter places and 2 primitive campsites.
Amager Fælled: is a largest park in Copenhagen area, located at Artillerivej 73B, 2300 København S. During May and September, the weather is good and it is possible to wild/stealth camp for free.
Christiania: Ask around, as residents are "officially" not welcoming to campers. There is a HUGE "No camping" sign. The only way can be ask the right people and go far away from the village. Rumors and stories of bad episodes plus general people attitude when you ask them for tips.. doesn't really push you to try..other places are better!
Other wild camping Resources can be found here.
Fredenshavn If you have a boat, or offer help on another persons boat, visit Pirate bay/Fredenshavn/ Peace Harbor/Pirate Harbor. Its a strip of water located just outside Christiania (pass the Christiania beach). The address is Refshalevej 28, 1440 København K. BIts a on-water squat community. It offers free water space to those who have their own boat or willing to live on other squatters’ boats. Your boat can not be taller than 2.05m and wider than 3.25m. Those selling/giving away their boats can be found at a Danish sales platform.
Copenhagen is a city whose dumpsters are a generous source of food. Ask the locals or check out Trashwiki for more information. Cheap places where to eat in Copenhagen
With free IKEA card you can drink unlimited free coffe
Sleepinheaven hostel, in Nørrebro neighbourhood can be entered also by strangers (pretending and looking like guests) and has 2 computers free to use (log out and delete your browsing history since there are lots of people using them).
Copenhagen Downtown Hostel also has a free WiFi. But usually there's a lot of other guests also using it.
There is free WiFi in all the public libraries. If you don't have a device, you can use computers at the public libraries free of charge. See libraries on the map. See also Accommodation
Shower & swiming
In summer there are some free (cold) showers at the public bathing sides along Sydhavnen ( 55.66338,12.56516 ).
Copenhagen can be extremely profitable for busking. Danish crown is a very good currency for that and the huge number of tourist mixed to the generally very high standard of living of locals can make you earn very good money. Go in the centre, pedestrian streets, as along the canal. No permit needed if you are less than three people, but there are time restrictions regarding what time you can play. Find information here . If you don't respect the time frame locals could come to you and gently ask you to stop. In summer there is a lot of concurrence though. In the information sheet it also says that you are not allowed to sell anything or collect any money, but it happened many times that the police car passed by and never said anything. Stroget is the street for busking
Free clothes, shoes
There is a free shop of clothes (take whatever you want for free) in Christiania. Just ask around.