Here's the prophetic truth: How you responded FIRST in your heart to this is the reason Father can or cannot trust you with riches. You are to be a conduit. You are to be His way to bless others (Blessed to be a blessing). You are to walk in perfect integrity. You are to have already made the decision on the right thing to do in this case without question. It should be instinctive. Don't wait till you are faced with this to begin to figure out whether to do the right thing. If you responded in finders keepers losers weepers or maybe Jesus put it there for me to find, you need to check your heart.
I try very hard to live this way and more I see how that relates to God's willingness to trust me. Many times I have argued with a clerk who gave me too much change or forgot to scan something or who undercharged me. Integrity in all things is the door to blessing.
You will never have what you need till you change your heart. No condemnation here, just asking you to think better of your character. Character precedes prosperity. The world will have you thinking otherwise. They will tell you the rich got rich thru corrupt character. I know the opposite is true, I know the very wealthy. I live among them. I have been very wealthy, twice. My character is still in training. Those who achieve ungodly riches fall quickly. I asked the Lord once, why I have made and lost so much money in my life, He told me that it was because I wasn't ready for all He wants me to handle. I want to be ready.
Jesus spoke to this very thing in Luke 16:10 "He who is faithful in a very little thing is faithful also in much; and he who is unrighteous in a very little thing is unrighteous also in much. 11"Therefore if you have not been faithful in the use of unrighteous wealth, who will entrust the true riches to you? 12"And if you have not been faithful in the use of that which is another's, who will give you that which is your own?"
And all thru the word of God this is a strong theme:
1 Timothy 6:9-10
But those who desire to be rich fall into temptation, into a snare, into many senseless and harmful desires that plunge people into ruin and destruction. For the love of money is a root of all kinds of evils. It is through this craving that some have wandered away from the faith and pierced themselves with many pangs.
A good name is to be chosen rather than great riches, and favor is better than silver or gold.
Better is a poor man who walks in his integrity than a rich man who is crooked in his ways.
Whoever trusts in his riches will fall, but the righteous will flourish like a green leaf.
The blessing of the Lord makes rich, and he adds no sorrow with it.
I won't argue about what you should have done. That's between you and God. I'll allow the spirit of God to check you out in this area. I know what I would do, but if you aren't sure.. you aren't ready to prosper.