A beta is software still under development that is made available to a select few to test, examine, and report problems they face. Beta testing allows developers to find problems they may have missed and fix them before the program is released.
Often there are two beta testing phases, open beta and closed beta. An open beta also known as a public beta refers to beta testing that is open to any user, who is known as a beta tester. Closed beta refers to beta testing that is only available to a select few individuals or company employees only. Many games in development will have an open beta for several months and allow anyone interested in the game to play and report problems.
Tip: Participating in a beta is always free and should never be purchased. Many scam artists will sell a copy of a beta program or the code to get into a beta to unsuspecting people wanting to play a game before any of their friends. Many times these codes are fake or disabled codes to play the game.