Capitalism, as I understand, and as EleventhHour alluded to, doesn't identify oppression and sin. Essentially, (it means in theory, but not usually in practice), if someone owns all the land, or all the air, or all the water, or something else essential to life, he can charge for that whatever he desires. It can in extremes be a justification for fascism.
In the bible, God made sure that everyone had the right to land, as everyone needs land to prosper. Fortunately, the Israelites weren't so foolish as to believe someone could legitimately own the air, or the water, or the sunlight, so there were no laws for these things. This is a lesson that modern man would do well to learn.
However, to distinguish from such foolish thinking as the above, and to distinguish from the "croney capitalism" communist sympathisers have made our current economic system into (i.e. using the government to oppress the free market, while at the same time, using capitalism to justify the ownership by corporations of public property such as land, air, water, sunlight, etc.), I believe a "free market" system is a better descriptor than a "capitalist" system.