Okay bye is another form of asking " are you joking me?". It can also mean "whatever" or "I can't believe he/she said that!". You can also use it when you see something that is not okay, disturbing, or really funny. It is commonly used in the female population.
Boy: " You look like Air Bud"
Girl: OKAYBYE! No I don't
Girl 1: " Did you see that girls camel toe?!"
Girl 2: "Yeah and i was like OKAY BYE!"
n. A game. Can be played by 2 - infinite number of players. One rule: usually employed at the natural end of dialogue or conversation, any player who says ‘okay bye’ first and then hangs up or leaves the room etc., wins.
In order to attain maximum effect, delivery of 'okay bye' must be extremely quick followed by immediate hang up/departure. When emailing, 'okay bye' should be spelt as one word -okaybye- to indicate the hasty delivery usually employed when speaking.
A quick way to end a conversation when you have other, more pertinent things to do. Often used when talking to old friends long distance.
It's a nice summary in that a) you acknowledge what has been said b) you verify that you need to go & are exiting the conversation and c) you will talk to them again soon.