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This is also an ideal situation for seller financing! What are the seller's circumstances?
30K sounds cheap for 20 ac! That could be big money in her eyes but at 82, you better do some due diligence! Do her heirs know she is selling and what do they think? That's because at 82, kids come out of the woodwork yelling that mom was taken advantage of and they get an attorney....you can have deal nullified easily if the kids get mom to say she wasn't thinking straingt! So treat her with kid gloves and they get upset if they think they need the kids permission, so tread carefully finding out.
At her age, an annuity income might be a better bet for her than a lump sum after taxes (state if any). She needs to consider what would happen to her cash if she went to a nursing home vs. a note which would be discounted for her to qualify for services.
Knowing what a seller needs and how best to structure the deal can keep you out of trouble, get you a much better deal and ensure everyone is happy.
A seller financed note could be assumable for your buyer as well, making the sale easier.
If interested there is alot of info here on seller financing or you can always ask....