the only way sure i can see for now is lending with collateral or lending on poloniex
it just takes a few bitcoin capital and you'll get a nice profit without any skills. you just need to find reliable people who need the money by offering good guarantees
Ya it is true that right now the best way is lending in this forum but for that you have to follow certain rules so that you should be get scammed and apart from that Saving Bitcoin in wallet is it self a big investment as the price is moving high so its value is also increasing automatically.