"For it is by grace that you are saved through faith and this not from yourselves, it is the gift of God not by works, so that no one can boast." Ephesians 2:8-9
It is like, suppose I were to give you a beautifully wrapped gift. You would accept it right? You would not give it back to me?
That is how God is. He offers heaven free. God Is Love.
"For God So Loved The World That He Gave His
Only Begotten Son, That Whosoever Shall Believe On Him, Shall Not Perish, But Have
Everlasting Life." 
God sent His Son, Jesus Christ to die for your and my sin. Jesus paid our penalty for our sins in full. He loves us sooooo much, that He died for us! How awesome!
Do You Know Him? Do You Want Him and have the assurance that when you die you will go to Heaven? Pray the prayer to accept Jesus in your heart!