Known as Free to Play, it is also a popular term used in the popular first person shooter game, Team Fortress 2. F2P defines players who are new to the game and are not well experienced. When Team Fortress 2 became Free to Play on 2011, F2P players recieve a free hat called the Ghostly Gibus along with Pyrovision Goggles. Since F2P players are unable to trade and recieve new hats, the Ghostly Gibus and the Pyrovision Goggles are the only cosmetics to wear, unless purchasing items from the in-game store. Any player wearing the Gibus and the Pyrovision Goggles are labeled as noobs by non F2P players.
Gamer 1: "Damn, I got dominated by a noob!"
Gamer 2: "How do you know he's a noob?"
Gamer 1: "Because he's wearing the Gibus!"
Gamer 2: "Oh, so he's an F2P player!"
In TF2, a f2p used to mean a player that doesn't have the premium version of the game, so they only have The Ghostly Gibus, and The Provision Goggles. Now, it's a general term used for when any player doesn't understand the unsaid rules of TF2, which consistent of "Don't kill friendlies" and other rules like "Trolldier honor fights." They are considered a F2P, since they are acting like a person who hasn't played the game for long, or don't understand the game.
*JoseGonzalez2004 killed Gamer*
JoseGonzalez2004: Ha you rbad.
Gamer: Really? I was being friendly!
JoseGonzalez2004: Your just bad!
Gamer: What a F2P.
F2P or fuck to pay is a term used when fucking to pay. Which basically means you're a prostitute. People who do F2P either have a sugar daddy or find random people to pay them. A person who does F2P is called an F2Per.