What our Lord God and Saviour Jesus Christ saved us from on the cross was death - and in saving us from death He saved us from sin. If you go to the Education section of this Forum you can read my Paschal Sermon in which I try to explain this.
I believe that truly a price was paid for us at Calvary, even a very great price indeed, quite literally an infinite price since the price paid was God Himself. This was the price God was prepared to pay to redeem us or buy us back from death and sin. This is what it cost God to redeem us back to Himself. The price was not paid to anyone in the legal or transaction sense - it's simply this is what it cost, this is the price God was willing to pay to redeem lost mankind.
I think Tony puts it well enough about salvation as healing. The Great Physician at great personal cost to Himself at Calavry provided for us the medicine to make us well, to save us or heal us from this fatal spiritual disease called sin, even His Body and Blood. And He founded a spiritual hospital called the Church, where we can receive this medicine.
Wherever did you manage to get hold of a copy of A Tiny Step away from greatest Faith? I thought it utterly magnificent but after giving my copy as a present to someone wasnt able to find another copy anywhere to buy.