Similarly, we don't go around bragging about our new "Chariots" to our friends – instead, we call them "cars." (Well, technically, a chariot is drawn by a horse, but you get the point.) So, just replace these old-fashioned words, and the meaning of these lines becomes clearer right away: dude, the car that can carry the human soul around is dirt cheap!
The speaker here expresses wonder at the fact that reading can carry your "soul" or imagination on a kind of joyride, and it's totally, one hundred percent free.