All value is perceived value. So, I believe voluntary trade of goods or services at whatever value both parties agree upon, is justified. The answer to manipulation during the transaction is 'knowledge'. Whoever has more knowledge, will gain more from the it (13 year old boy in this case).
And it's immoral for sure, but being moral will nullify any possibility of profit during the transaction on in future transactions. Choose yourself!
I submit your comment is a perfect example of how hubris leads us astray.
Value, however you think of it, exists whether you perceive it or not. Let's say you need to buy some compressed gas for your cutting torch. The market sets a price on that gas, and that is the value you agree it has.
On the way home with your tank of compressed O2, there is a terrible earthquake, and you are trapped in a collapsed overpass. A water main is leaking, and soon you are trapped in a tiny bubble of air, underwater.
Fortunately the bottle of compressed O2 had value you never perceived, until that moment.
Not only does this point out that we cannot perceive all the value that exists, it also completely negates your supposition that knowledge leads to the ability to profit from other's ignorance.
What you neglect with your hubristic disregard for morals is that money really isn't valuable at all. When you are trapped in a bubble, all your BTC won't have any value at all.
What if you are in that situation, and you have been what you would consider a savvy businessman, persistently taking advantage of others in various deals. After you do this, you become known as someone without scruple.
In another crushed car next to yours is a person that has always insisted on fair dealings, accepting less money, but greater regard from their peers, unlike you. The community is responding to the earthquake and all your neighbors are coming to save trapped people under the overpass. They only have time to save one person.
How smart was it to rip all those people off?
You can't predict what the future will bring. I assure you that the regard of your peers is far more valuable than money, and your own self respect - not conceit, born of hubris - can never be matched by any amount of gold.