The online part of Grand Theft Auto V is launching on October 1, 2013 for anyone that has purchased the latest game in the series, free of charge. Multiple pieces of evidence have been discovered that point to Rockstar offering micro transactions as a means of covering its costs for the online portion. In-game cash packs will be offered for amounts ranging from $100,000 to $1.25 million, but these packs won't necessarily be "pay to win" as the purchases in some games. High end equipment won't be immediately available, instead requiring players to level up their characters before accessing more powerful items.
Source: Ars Technica