Finders keepers, losers weepers is a children’s rhyme, meaning that if someone finds something, 

they are entitled to keep it (even if it belongs to someone else). It’s also possible to say only the first part, as in finders keepers.

For example:

Jake yelled finders keepers as he dashed toward the house 

with the sparkling ring he had discovered.

A: “Hey Bob, that’s my favorite toy!” 

B: “But I found it out on the playground, Tom. Finders, keepers, 

losers, weepers!”

A: “I’m pretty sure those are my baseball cards.” 

B: “So? Finders keepers, losers weepers.”

My umbrella has not been returned. 

Obviously, someone picked it up and has made no effort 

to find the owner. Finders keepers.

I just found a hundred dollars on the ground. No one was around, so I picked it up and put it in my wallet. Finders keepers, so it’s mine!

Tradução: Achado não é roubado.