* Apps with ads in them. Easy enough to churn out, but decreasing revenues and most of the high earning adverts are the scummiest. Low value and of low moral usefulness. * Solar Panels. In the UK, the government pays you per kWh generated. Needs an upfront investment, but stable income and you reduce your own energy bills. See http://shkspr.mobi/blog/tag/solar * Renting out property. Needs a much larger initial inves…
Most people I know who do well in that space do so after several years. Once they learn how to be a landlord, learn the quirks of the market they invest in, etc, it can be pretty low stress, although not necessarily hands off.
But if you're just starting out, you should expect to make some mistakes and run into some headaches as you figure things out.