There are many ways to earn Bitcoin. You may engage to mining, investing, bounty campaigns and air drops. The easiest way to acquire an amount of bitcoin is to invest but you may also consider joining bounty campaigns. Personally my token holdings of not onky Bitcoin are mostly from bounty projects. I do receive token rewards from bounties in which I used  to trade for Bitcoin. Mining is also a good way in order to acquire Bitcoin but I would say it would be costy in a sensr that you would need equipments such as PC, and ofcourse it would consume electricity ( bad thing if it is expensive in your country), and time also. I do believe that there is no such thing as "easy" way, every method have weights including financial, time , and effort matters.

I am still into bounty projects even if most of the projects are failing and even if the requirements or standards in order to be able to participate is more strict.