Cost: Free, except beware of parking in the wrong spot (as of May 2014)
Location: 1008 Baylor St, Austin, TX
Website: http://www.yelp.com/biz/austins-graffiti-park-austin, https://www.facebook.com/HOPEOutdoorGallery
This place is damn cool. Four levels of walls from an abandoned Condominium project (due to poor results from a soil sample). In cooperation with the city, an organization called HOPE (Helping Other People Everywhere) started maintaining the place and facilitating it as a place where public art is welcome. Now the place is filled with both excellent and horrible artwork, and it continually changes every week. Better than most art galleries I’ve ever visited. Creative talent all over.