Street art has officially entered the world of fine art, regardless of your opinion on the matter. When once it may have been thought of as mere graffiti, street art has found a place within art galleries, museums, and on the walls of art collectors and aficionados. From the ever-elusive Banksy to the iconic work of the late Jean-Michel Basquiat, street artists and their work have been fetching top dollar prices at famed auction houses for years, breaking down the hazy line between high and low art. Hopefully, other relevant and talented street artists, like Blu, JR, Swoon, Vhils, Space Invader, and Roa, will be seeing some top dollar action soon. In the meantime, here are some of the most expensive sales seen yet!
Banksy

Banksy is an England-based artist who combines his acerbic wit with commonly seen images to create controversial political statements. However, his commentary isn't limited to paint and stenciling, as he's also been known to place objects in meaningful ways. For example, in 2006 he trussed an inflatable doll up in the style of a Guantanamo Bay prisoner and put it inside the Big Thunder Mountain Railroad ride at Disneyland in Anaheim, California. In 2010 his first film, Exit Through the Gift Shop, debuted at the Sundance Film Festival and was applauded for its unflinching portrayal of street art and what makes an artist credible and relevant.

Photo Courtesy of Banksy Official
Banksy's 2007 Keep It Spotless piece, which is a defaced Hirst painting, sold in 2008 in a Sotheby's Auction for $1,870,000. His 2000 work, Simple Intelligence Testing, was also sold in 2008 by Sotheby's for $1,265,120, and his 2006 The Rude Lord (which is an original 1776 Thomas Beach portrait Banksy altered with a middle finger gesture) was sold for $320,900 in 2007. Banksy's 2005 Vandalised Phone Box was sold in 2008 by Sotheby's for $605,000, which is a phone box that was sawed in half and pieced back together to create an "L" shape - originally seen in Soho Square, London. Lastly, his 2000 Space Girl and Bird, which is spray paint on steel, was sold by Bonhams in 2007 for $288,000.

Photo Courtesy of Bonhams
Jean-Michel Basquiat

American artist Jean-Michel Basquiat got his start as an unknown graffiti artist in New York in the late 1970s and by the 1980s become a beloved and acclaimed neo-expressionist and primitivist painter (he died in 1988 at the age of 27). With much of his work critical of social hierarchies, such as segregation and poverty vs. wealth, his art will stand the test of time because humanity will never cease to struggle with maintaining a balance.

Photo Courtesy of Basquiat Estate
Many famous names have acquired a Basquiat piece for their own, including Madonna, Leonardo DiCaprio, and American hedge fund manager Steven A. Cohen. In May 2012, an auction at Philips de Pury in New York set a world record for a Basquiat work, selling his 1981 Untitled for $16,322,500. While much of his work sold today is on some type of canvas, an original piece on a chunk of wall would most likely go for the largest amount of money, as it is the most rare.

Photo Courtesy of Philips de Pury
Keith Haring

Over the years Keith Haring's iconic work has become a visual language. Beginning with chalk drawings in New York subways, his simple representation of the human form is now one of the most recognizable images today. Expressing concerns with death, birth, war, and love, Haring's use of color and bold lines helped launch him into the public eye, building relationships with other artists of the time, like Basquiat and Andy Warhol. Haring died at age 31 in 1990 but his work has only continued to gain more critical acclaim and popularity, with pieces in a number of museums, including New York's Museum of Modern Art, Los Angeles County Museum of Art, and Centre Georges Pompidou in Paris.

Photo Courtesy of the Keith Haring Estate
While much of his work that's sold through auctions span a range of mediums, from canvas to sculpture, it's his Subway Drawings that are the real prize. Due to the difficulty of authenticating them without a doubt, they can be tough for auction houses to vouch for, so you're more likely to see them on display at museums than you are in an auction. His work is relatively cheap compared to Basquiat, especially for the quality of the art, and according to Gallerist NY, the most brought in at auction for a Haring is $2.8 million, which was an ink-on-tarpaulin work from 1982 that Christie's New York sold in 2007.

Photo Courtesy of Sotheby's