I think the best source of bitcoin is trading. After that it may be mining or one can earn bitcoin from bitcoin forums..
Yes, it is true, but taking into account the important skills required to succeed in trading, perhaps this option is not suitable for everyone. That is why I still think purchasing bitcoins with fiat money earned from ordinary jobs is the best, the more convenient way to acquire bitcoins.
That is the simplest way to get bitcoin. But if we gain skill in trading, it can be good investment, because trading could give big profit for the skilled trader. So I think the best source of bitcoin is from trading.