David gave an offering of $1.5 billion worth of gold and silver from his personal bank account. Text:1Chronicles 29:9
Then the people rejoiced, for that they offered willingly, because with perfect heart they offered willingly to the LORD: and David the king also rejoiced with great joy.
Although he’d already given $5 billion toward the building of the temple from his government treasuries, this gift was from his own personal wealth. Not bad for a shepherd boy! David was prosperous. When he gave, the people were so blessed that they started giving spontaneously too-to the amount of $3.5 billion. So altogether, it was a $5 billion spontaneous offering! Then the people rejoiced, for that they offered willingly, because with perfect heart they offered willingly to the LORD: and David the king also rejoiced with great joyThen David started praying in verse 10. He glorified God-recognized and acknowledged Him. What had happened that day was supernatural and he placed value on it, thanking God and saying, “Lord, all we’ve done is give you that which was already Yours. Everything we have You gave it to us in the first place. David started thanking God for the blessing, remembering where it came from glorifying and thanking Him
**Text:1Chronicles29:18**
O LORD God of Abraham, Isaac, and of Israel, our fathers, keep this for ever in the imagination of the thoughts of the heart of thy people, and prepare thier heart unto theeSo giving with open and freeness of mind is very essential in a christians life 
So lets endeavor to give good gift without expecting something back in return for the lord will reward us bountifully in ways we dont expect.
Stay blessed