There are many ways and ideas to start passive income, ideas from btc mining to sell on commission, google ads commission is another method to earn but i have here a great idea to start the passive income
Setp 1:Register on web sites where you can sell any product like amazon, shopify, Aliexpress and who ever you like most.
Step 2:Search the product which you like most and easy to sell for example if you consider T Shirt which is the easy one to sell out.
Step3: Search the Chinese manufacture of the product you have selected, if you see alibaba and aliexpress, you can find many low cost manufactures.
Step4: Search the low cost designer on fiverr, upwork, guru or any other gig based website
Step5: Search the marketer personal on up work, fiverr and on guru.
Finish:Wait almost 3–5 months to generate sales.
If you are succeeding in above idea what i see many times the peoples generate from 1500$ to 3000$ on monthly basis, but depends on the abilities of person you hire after some time you may found the new ways to increase your income.There also alternate methods in case of you are not happy with Chinese manufactures but the whole idea is to always on low cost from shipping side. There are five great designer i found very comfortable to me.