New games whenever I buy them, unless it's a game that I can't find new or it to expensive new.
Infinite Space comes to mine. A new copy, sealed and depending on the version goes anywhere from 75 to 300 dollars. (Low end is the UK release, high end is the US release) A used copy? 25 to 75 dollars... and thats just for the cartridge, not including the case or any artwork. Used, with case and artwork, varies depending on quality but can go anywhere from 50 to 125 each.