* 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…
It also required upfront confidence in the sustainability of the government subsidy. In The Netherlands a lot of now-solar panel owners decided to invest because of subsidies, but last year the government decided to stop the subsidy for 2016. Especially with the low energy prices, that makes it a net loss for a lot of people.