If you want to earn you need to invest.
Don't feel regretting when you will invest to bitcoin. Just buy some alt coin like monero and it will give you decent return.
they have free opportunity to earn bitcoin even you dont have capital or 0 investment like signature campaign by doing posting yku can earn bitcoin but you need to rank up your account to earn good. You can service like selling bbcodes and designing for sure you can earn a lot of money if you do this. Other people also become campaign manager to the campaign but this is not easy you need more time and effort . But if you want to invest its your choice. Thats right monero gives you decent profit.
Signature campaign is a good way to collect free bitcoins but you need to be satisfied with your earnings as you will never make huge income from it and you can multiply your earnings by selling your services if you have any specific skills but that will also be an time consuming process to earn 1 btc to earn that amount quick I think trading is the only and best choice.