Money for upgrades

[Josh Tonecha]

Let's say hypothetically I was interested in a home that I knew needed some upgrades to maximize rents. If I can qualify for a 100,000 and the house is listed for 90000 can I make a deal with the seller to pay him the full 100,000 I can get but he returns $10,000 cash that will be used for drywall paint carpets and other non essential upgrades?

Is this possible/legal or commonly done and I'm just stupid?

Thanks for any insight!