First play Blue Version until Virdian City.In this game choose the pokemon Bulbasaur first when Oak let you have one of his pokemon.Than go to Virdian City mart and buy 4 pokeballs.Catch 2 pigey and 2 Ratata.Save the game.Play Red Version.Choose Charmander.Play until Virdian City.Now trade with the blue Version 1 Ratata for the Charmander.Start new game.Play until Oak let you choose his pokemon again,choose Squirtle,play until Virdian City,trade with blue Version,trade 1 pigey for the Squirtle.Now you Blue Version have 5 Pokemons!Isn't it great?Than Continue playing the game.Play both versions until Celadon City.