No unofficial bootlegs should ever be bought. Unfortunately it is not rare to see many of them go on sale for prices low or high on ebay or other websites, and I myself must admit that I have more than once given in to temptation and bought a couple.
But it's completely outrageous what that guy did. He printed the recording I made for everyone to share freely and put it on sale without even bothering to ask for a permission (which I can't give of course, but that I would have never given if I had the authority to do so) and solely for the purpose of getting some money.
Ad ogni modo, Luigi, mandami un PM, possiamo parlare del concerto e di come fartelo avere in un'altra sede