Nobody with a stake in your deal gets to pay your mortgage on the side. Money like that has to flow through closing, disclosed and capped. When a seller, builder, agent, or lender contributes toward a buyer's costs, the industry calls it an interested party contribution, and the rules are strict. It must show up on the settlement paperwork, it counts against the loan program's cap, and it arrives as a closing credit or a properly funded temporary buydown escrow. It never takes the form of a third party quietly making your monthly payments. The caps vary by program: conventional allows 3 to 9% depending on down payment and occupancy, FHA allows 6%, VA allows 4% plus certain loan costs, and USDA allows 6%. These credits also can't fund your down payment or reserves. The legitimate version of this pitch is a transparent credit: a seller credit toward closing costs, or a lender credit tied to your rate, shown on your Loan Estimate and Closing Disclosure. That reduces the cash you bring to the table, which can leave more of your own money in the bank for the early payments. Same practical effect, done in the open. If someone offers to cover your first several months of payments in exchange for full asking price, ask exactly how it would be documented in the contract and disclosed to the lender. Anything that has to stay off the settlement statement to work is a deal to walk away from.