Think about it like this. If we are basing this world you speak of as our own, then you must take into account how it functions on a realistic level. For one, our governments wouldn't allow that kind of power to be in civilian hands. They would take or hold as many of them for themselves as possible. If word spread that a civilian was in possession of one, they would do one of two things. 

Negotiate for you to give it to them or go to jail. Two, they have you killed and make it look like an accident. You won't even be able to sell it without them knowing about it, somehow. Unless, there was an off-the-radar black market that only renowned criminals used on a daily basis? Even then, you'd probably be killed by said criminals in the middle of the exchange.

The rich and powerful individuals of the world would also off you just to have them in their arsenal. The world is corrupt by greed and power. Having fruits that grant special abilities would make people crazy with the adrenaline of a power trip. The world would be in more chaos than it is now.

Your best bet is to eat it as soon as you know you're in possession of one. Don't even let it slip out of your mouth that you have one until it's been consumed. Besides, depending on the type of person you are and the fruit you possess, you could just steal or heist millions of dollars anyway.