I do . ( keep and flip ) several per month, all double digit cash flow, Good luck,  PS team is the most important ingredient 

The market I invest in is down noticeably (& I own a condo that is down substantially in my market due to nearly a decade of overbuilding) and I’m still well into double digits.

I was expecting double-digit returns from Prosper, and am very disappointed with my low single-digit results.Prosper does issue an annual 1099 reporting earnings for my 401k, which I ignore for my tax filing.I would suspect that you could deposit personal funds into your 401k's Lending Club account and call it a contribution, but I would check with Mark Nolan to be sure.But it seems like to would be simpler and cleaner just to deposit the full $18K to your brokerage account and move funds into Lending Club from there.

All with double-digit returns and plenty of upside through forced appreciation. 

Couple hundred bucks a door cash flow, double digit ROI, and yes the prices appreciate and you build equity.Anyone who disagrees, is missing out.

I charge $600 a week for a 3 bedroom house that costs a 4 digit number to buy and a 3 digit number to furnish. 

The key word will be underpinning for you if you have to dig, it's a pain but you are going to live there, do it.  

Retirement plans are best suited for lending.On a positive note, it's not a difficult business to learn and earn double digit returns with very little risk, if you're careful.

Couple hundred dollars cash flow, and double digit ROI.

I buy mine from Multifamily NW (they have digital signing built in, and after the initial fee the annual subscription for unlimited use of the forms is under $50 for 5 or fewer units).You might also consider getting your lease from the local landlord association.