Depends on one's expertise and preference. Some are not interested on doing bounty campaigns so the best way is to invest thru exchangers which is less complicated. Some are into mining but to countries wherein electricity is expensive, such method is not advisable because it would be costly. Also, you'll need a powerful set up in order to make mining more profitable. Bounties on the other hand is a good method but difficulty is higher than before. I am pertaining to bounty requirements nowadays. Merits are now a huge factor in order for a user in this forum to be accepted as well as forum rank. Unlike before wherein there are numerous campaigns at the same time which is capable to accept more users making it a profitable method in order to earn Bitcoin or other cryptos.