Tbh its impossible for a newbie to earn 1-2btc per month without investing. It will take time before you are able to earn such amount from nothing. It could even take a year or more than that.
And they really need a big investment to earn 1 - 2 BTC a month. Just for example if you invest in a company that gives a return of 5% per month, you need to invest 20 BTC in order to have 1 BTC earning. Unless you have skills or join an affiliate system with a well build group, it is more likely not possible to earn 1 - 2 BTC a month.
Just like real money, there is no instant way to do it. Even if there is instant way, usually it provide a RISK for example : trading or gambling
Or you can purchase mining hardware ( most of them are expensive )
Or you can invest 10% from your main salary every month
with gambling or trading, 1 BTC earning still needs a large amoung of fund, not saying it is not stable because altcoin market is unpredictable.