Originally drawn for a Buck Rogers themed cover to Famous Funnies (published by Eastern Color Printing/Famous Funnies Inc), it was rejected as too violent. Ended up as the cover to Weird Science-Fantary #29 for E C Comics in 1955 after Frazetta cut a special deal with Bill Gaines (for $30.00). In order to keep the original artwork (Gaines usually required complete ownership of the original art) Frazetta was paid half-price on the standard cover rate.
Frazetta told Gary Groth, in the Comics Journal magazine 1994 interview with the artist, that Frazetta considered this piece of artwork his peak work in his pen technique.
The black and white art was eventually hand-colored by Frazetta as a print issued by Frazetta-impresario Russ Cochran in 1971. For an interesting story about that print and the signed-hand-colored run, see this story at Golden Age Comic Books.
The original artwork sold to Joseph Halperin for $380,000 in May 2010. Halperin is the co-founder of Heritage Auctions, which handles a great deal of original comic book and phantasy art, among other collectible items. The previous record for a single piece of American comic book art was a Wally Wood cover to EC’s Weird Science #1.

Conan The Buccaneer (aka 'the Destroyer') sells for $1.5 million USD
Conan The Conqueror (aka 'Berserker') sells for $1.0 million USD
Frazetta Conan the Buccaneer Original Cover
Weird Science Fantasy ink cover art sells for $380,000
"Warrior with Ball and Chain" (aka Flashing Swords #1) sells for $150,000 USD
"Spec Art" comics page from the 1950s
Easy Way to a Tuff Surfboard 1966
Reconstruction of the Frazetta "Nina" page
Frazetta Beauty and the Beast - Top panel to original Nina Page