Have you ever bought anything without spending any money?
Yes. When you use a gift card given by someone to complete a transaction of trade.
Jesus Christ invites you, who are thirsty and hungry in heart to come to buy and eat from Him without money and without cost (Isaiah 55:1)
Faith is when you open your empty hands in front of God and acknowledge that Jesus Christ is a fully man to bear your sins and also a fully God to give you forgiveness.
As a result, your repentance is the response from your heart that has received His forgiveness and eternal life.
Then, God comes in to live in you and you will rely on Him and love Him and other people as yourself.
It’s the most “happy ending” for your earthly life which may exult in Him in any situation.
“But let all who take refuge in You rejoice; let them ever sing for joy, and spread your protection over them that those who love your name may exult in You.” Psalm 5:11 ESV