50 Cent -- Desperately Seeking Renter ... for My MANSION!!

50 Cent is looking to make a quick buck off one of his greatest assets ... his massive Connecticut estate is now available for rent.

Since he filed for bankruptcy, 50's been trying to dig out from under his debts, and during a meeting of his creditors on Wednesday ... his lawyers revealed the rapper is now trying to sublet the mansion which features 21 bedrooms, 9 kitchens, and even a freakin' CASINO!

No word on how much 50's asking, but bankruptcy docs show he'd been paying $72,000 per month just for maintenance on the place.

The mansion is financially cursed -- previous owner Mike Tyson went bankrupt while living there, and a Lithuanian businessman also went belly up when he called it home.

Talk about a money pit.