What are fair terms for a private money lender

[Jessica Flint]

I currently own 8 units.  Up to this point, I've financed most of the down payments myself with the exception of a little family money.  I'm ready to venture out and start asking some friends who would make great private money lenders.  I don't want any partners.  I want to have them paid off in as little amount of time as I can afford.  I'm looking long term, so I'm not super worried about great cash flow yet.  What would be a reasonable offer? Terms? etc? I want them for the down payment only.  I plan on financing the rest myself.  They would be have a lien on title, as collateral, until I pay them off completely, correct?  Is 6% interest for 6 years reasonable? Or do I need to offer something more aggressive?  I usually need approximately $25,000-30,000 down.  The market in my area is very aggressive and hard to find great cash flow deals.  I can't afford more than about $400/month for the investor.  Suggestions??