Help with seller financing offer. And the NUMBERS!

[Tony Velez]

Hi,

Here is the story. This house has been on the market for over 2 years. Its a cute little house that always pops up in my searches. I've only seen the outside of the house. Last year they were asking $85,000. Now they are asking $77,900. It looks like he has no mortgage. 

I found the contact information for the owner. I plan on writting them a letter. I've been reading alot on owner financing. The problem I'm having is figuring out how the interest rate works. 

I would like to offer $75,000 with 10% down payment.... with an interest rate of 6% amortized for 30 years. 

Sounds like I know what I'm doing. BUT.... I can't figure what my monthly P/I would be to the seller. 

Also what if we decide on the same terms but a balloon at 5 years? 

Please help me figure out how to do the math?

Thank you

Tony V