If I had to pick the best source of recurring income right now, it would be crypto currency mining. For a one-time puchase or period rental, you receive recurring income from mining for a period of up to life. Genesis-mining.com is probably the world's foremost seller of mining contracts and I can wholeheartedly recommend them. Simple to purchase process, even for the uninitiated and totally passive earnings after that.
*Use this evergreen code Hwvo6t for a 3% discount on every purchase from genesis-mining.com
**Personal note: Bitcoin mining is now slower, after the recent "halving", so I am buying mining capacity for the soon to launch Zcash. It will start out on 28 October 2016 in the same way as did Bitcoin and not by ICO. Soooo- Opportunity here for early mining, folks! (Btc mining is still profitable, albeit slow and steady). There is also Ethercoin mining in the pipeline- this is interesting to me since KIBO crypto lotto will be run exclusively in Ethercoin. An international lotto like this should generate good, consistent volume demand which all requires mining.
I can also offer a second possibility: KIBO International crypto Lotto. Currently in pre-launch phase and offering limited preferential shares which will yield a recurring passive income for life. There is also a limited number of platform reseller positions available which will pay a commission every time a player buys a ticket on your platform or wins.