Complicated Seller finance deal

[Bonnie Lloyd]

I have a home for sale, price 900k.  Not free and clear, has about 480k left on mortgage.  Someone asked our realtor if we would be open to seller financing.  We are early in process but I am leary of everything, as this has been our biggest financial investment so far and don't want to get screwed.  He has told the realtor he make 30k a month, but he is Canadian, doesn't want to get loan thru bank because he wants to buy and use it as a tax write off with his company.  He has said he might do 200 to 300k down and pay the rest over short term maybe a few years...just when he casually discussed with realtor.  This is way over my head.  What might be wrong or right with this?  is this a gift horse or a disaster waiting to happen?