Taxes on interest for lenders

[Kevin Kong]

Hello BiggerPockets!!  I was listening to a biggerpockets podcast and i forget which episode it was, but they talked about it for a little bit.  Does anyone know how much tax gets taken out of the interest rate for the lender?  Im trying to offer the owner a owner finance option with a 0% interest rate but higher purchase price.  Since you get taxed on both I wanted to do what they talked about and give more on the top end but little to no interest rate.  Let me know if this makes any sense.

Business asking price is 569k in illinois.  With 5% interest on a 20 year loan it would be around 40100$ total.  I wanted to add an extra 30k to the asking price with a 0% interest rate.  Does this seem completely dumb on my part?  Would anyone take this deal if offered to them.  Thanks again for your help