Stockholm is a highly cultural city, with countless galleries and museums -- many of which can be enjoyed free of charge or at a discount as long as you plan ahead. Your best bet is to get a Stockholm Card (www.stockholmtown.com/stockholmcard), which can be made valid for 24, 48 or 72 hours. It provides free entry to 75 museums and attractions; unlimited transportation on the city's public underground, bus and commuter train transportation systems; and free sightseeing on certain boats. The catch is it has to be purchased at least 48 hours in advance.
Some of the included, tourist-friendly destinations are Vasamuseet (Galärvarvsvägen 14, 102 52, Stockholm; tel. 011/46/8-519-548-00; www.vasamuseet.se), a preserved, circa 1628 sunken-ship-turned-destination, and Nobelmuseet (Stortorget 2, 111 29 Stockholm; tel. 011/46/8-534-818-00; www.nobelmuseet.se), a glinty locale where visitors can uncover the history of the Alfred Nobel, the Laureates themselves and the Nobel Prize.
If you opt not to purchase the card, do your research. Some museums, such as the Arkitektur Museet (Arkitekturmuseet Skeppsholmen, SE-111 49, Stockholm; tel. 011/46/8-587-270-00; www.arkitekturmuseet.se), feature free admission days. Afterwards, consider stopping by the Sveriges Riksdag (100 12, Stockholm; tel. 011/46/8-786-40-00; www.riksdagen.se), where parliament meets. Guides provide complimentary tours with no advance notice. Tours are held in English on Saturdays and Sundays at 1:30pm September through June 15. During the summer, tours in English are held every weekday at noon, 1pm, 2pm and 3pm.
Another way to save a few bucks is to skip the rental car. The city's transportation system is extensive and easy to navigate. Moreover, exploring Stockholm by foot is enjoyable. The archipelago of islands boasts water views at every turn, and parkland is plentiful. A good place to start is the cobblestone streets of Gamla Stan/Old Town, which give way to the Royal Palace and Storkyrkan cathedral.
Or, you can check out Djurgarden, a heavily wooded, centrally located island where visitors get shuttled around on old trams. If weather permits, be sure to visit the open-air Skansen (SE-115 93, Stockholm; tel. 011/46/8-442-80-00; www.skansen.se), a bevy of attractions chronicling Sweden's history. There's also a zoo and aquarium -- as well as cafes and shops -- on the grounds. (Adding to the appeal, this is yet another freebie admission with the purchase of the aforementioned Stockholm Card.)
Not to be forgotten is Stockholm's theater scene. During the summer -- when daylight lingers for upwards of 18 hours -- the city hosts Parkteatern (tel. 011/46/8-5062-0100; www.stadsteatern.stockholm.se), free, multi-genre theatrical performances held at parks citywide. Often, audience members -- whether or not they have beaucoup bucks -- pack picnics to enjoy while watching the shows.