DayZ has already garnered a fan following despite being a mod for an existing game, but a standalone version of the game is in the works for release before the end of the year. Creator Dean Hall has stated that in terms of what the team wants to accomplish (some of which was outlined in our interview on the game), the alpha version absolutely has to be out by the end of the year.
Hill has not named an exact price, but he has made it clear that the standalone version will be cheap. He's also made a point of stating several of his longer-term plans for the standalone version, including the spread of diseases, makeshift first-aid remedies, and the eventual inclusion of vehicles. All of it is very ambitious, but that's part of the reason that the team is dead-set on having the standalone game out before the end of December.