Oh, come on. Mormons don't "buy" their way into heaven, any more than anyone else can. Jesus made it clear that no one could enter the Kingdom of Heaven without being baptized. Since baptism is only available on this earth, and to a limited number of God's children who have even heard of Christ throughout human history, it would be hugely unfair for some, through an accident of birth, to be consigned forever outside their Father's home. Mormons believe that, through proxies )who receive nothing for performing this saving work) those who have passed from this life into the next without the opportunity to hear the word of God and accept baptism into His flock will have that chance. We do the work, but it is up to the person to accept it.