Buyer on a owner contract made payments that were 2 cents short for first 153 months and then started paying 98 cents extra per month. How do I figure out the final payment? According to the contract final payment will be due November 2016. It was $28,200.00 for 30 years at 9% interest with first payment of $286.02 starting December 1st, 2001. This buyer has history with both myself and my Father anywhere from constantly claiming "the checks in the mail" to trying to pass off a different ($40,000 less! ) agreed on selling price so I don't trust him at all. Recently he sent me a print out showing that he had paid $287.02 every month but I pointed out what he has really paid & he now agrees. Please help me figure out the final months payment amount.

Just an opinion.

.02 X 153 months = $3.06
If you were to actually compute interest on that for 153 months it would come out to be something like 10 or 12 cents.
Plus you said that he paid $0.98 extra each month but didn't say for how long. If he did that for 4 months or more you came out ahead.
Do you really want to worry about $3.18. Not worth the ink to print out.
Forget the .02 and go to settlement. Reduce the final payment by $0.98 times the number of months paid less 4.

Do you have Excel or another compatible spreadsheet? Excel has an amortization schedule template. You can then plug in the actual payments and see what balance is due.