One of the less helpful aspects of much theological discussion about atonement is the tendency to talk in terms of competing theories of Christ’s cross-work.  John Stott has a helpful comment about this in The Cross of Christ (p168):-

“Images” of salvation (or of the atonement) is a better term than “theories.” For theories are usually abstract and speculative concepts, whereas the biblical images of the atoning achievement of Christ are concrete pictures and belong to the data of revelation. They are not alternative explanations of the cross, providing us with a range to choose from, but complementary to one another, each contributing a vital part to the whole. As for the imagery, “propitiation” introduces us to rituals at a shrine, “redemption” to transactions in a market-place, “justification” to proceedings in a lawcourt, and “reconciliation” to experiences in a home or family. My contention is that “substitution” is not a further “theory” or “image” to be set alongside the others, but rather the foundation of them all, without which each category lacks cogency. If God in Christ did not die in our place, there could be neither propitiation, nor redemption, nor justification, nor reconciliation.

Complementary images, then, are what we should be looking for in Scripture, then, rather than competing theories.  I have found the following list a helpful summary (it’s adapted from Bruce Shelley’s Theology for Ordinary People):- 

• The bank – We were in hopeless debt, and Jesus paid the debt for us. (Lk 7:41-50)
• The slave market – We were slaves, and Jesus came to the marketplace to redeem us from bondage. (Eph 1:7)
• The law court – We were condemned criminals before the judgment seat of God, and Jesus bore our penalty in order to set us free. (Rom 15:16)
• The temple – We were unclean Gentiles, excluded by our sin from the presence of God in the temple, and Jesus gave himself as a sacrifice to consecrate a way for us to approach the throne of mercy. (Eph 2:13-14)
• The home – We were children in disgrace, far from home, and Jesus brought us back to the family circle. (Eph 2:18-19)
• The battlefield -We were captives confined to the fortress of Satan, and Jesus broke in to deliver us. (Col 2:15)
• The hospital – We were suffering from a fatal disease, and Jesus restored us to health 1 Pet 2:24.

Or, as J. Oswald Sanders helpfully puts it in Christ Incomparable, p195, the atonement:-

• is moral in character. It originates in and manifests the unselfish and disinterested love of God. This love is a source of moral stimulus to us, and can break the hardest of hearts. Heb 2:9 1 Jn 4:9.
• is a commercial transaction. It is a ransom paid to free us from the bondage of sin. Mt 20:28 1 Tim 2:6.
• has legal significance. It was an act of obedience to the law sinners had violated, Gal 4:4-5 Mt 3:15. It was a penalty borne in order to rescue the guilty, Rom 4:25.
• is medicinal in its effects. Sin being represented as an hereditary and contagious disease, Isa 1:5-6, Christ’s death provides a panacea, Isa 53:5 1 Pet 2:24. See Mt 9:12-13.
• is sacrificial in nature. It is a work of priestly mediation, reconciling man to God, Heb 9:11,12,14,22,26.