He said on the post: “My crib is almost finished in AFRICA. I’m gonna have the craziest House warming party ever.”
In July he filed for bankruptcy days after a jury ruled he had to pay $5m (£3.2m) to a woman suing him over a leaked sex tape.
Forbes estimated in May that 50 Cent’s net worth was $155m.
He doesn’t mention on Instagram where in Africa the new house is located, saying only: “I’ll explain later. I got a good life Man.”
The video shows people working outside the house but gives few clues to its location.
Reaction across the media and Twitter has been that of surprise given he had filed for bankruptcy.
The entertainer, whose real name is Curtis James Jackson III, said at the time that filing for bankruptcy was a “strategic business move”.
Chapter 11 bankruptcy gives time for a business to re-organise finances while protecting it from creditors’ demands.
The Grammy-award winning rapper’s business interests have included clothes, boxing, drinks, and mining.
His stake in VitaminWater reportedly netted him tens of millions of dollars when Coca-Cola bought the drinks brand in 2007.
His 2003 album Get Rich or Die Tryin’ catapulted him to global fame.