Maybe you aren't a fan of the 2d20 system but you are a fan of John Carter of Mars and the Sword & Planet genre. At these prices, I'm in it for the source material. I can always convert to the OSR system of my choice later ;)
For 9.95, you get the Starter Bundle for John Carter of Mars. It includes the John Carter of Mars RPG, John Carter Narrator Screen & Kit and Barsoom and Korad maps.
For about 30 bucks, you add in the Phantoms of Mars Campaign Guide; three "Era" supplements that describe different phases of the Martian sequence (Dotar Sojat Era, Jeddak of Jeddaks Era, and Prince of Helium Era); and two 52-card print-and-cut decks of artwork (Landscapes and Locations Deck and Characters and Tokens Deck).