Get a copy of his speech to the Democratic Association of Brussels at its public meeting of January 9, 1848. In it he concludes, "...the protective system of our day is conservative, while the free trade system is destructive. It breaks up old nationalities and pushes the antagonism of the proletariat and the bourgeoisie to the extreme point. In a word, the free trade system hastens the social revolution. It is in this revolutionary sense alone, gentlemen, that I vote in favor of free trade.
Come on, man... are you that intellectually lazy? You would walk into an economics class trying to convince them that Karl Marx was for free market capitalism based on that? In that entire text he rants about how much he hates free trade and the people that support it... over and over and over again... and in one quote throws in a tounge-in-cheek rhetorical device saying he would support it over the current system only because he knew that the people of that day were too dumb to understand it, thereby making it easier for his side to win them over with their class warfare demagoguery. But, no... Willie Green found you one little quote that you read which appears to say Karl Marx was a free marketeer, unbeknownst to every student of economics the world has ever heard from. Amazing.