Let's set aside broader economic concerns for just a moment and revel in some goodness: New cars are going cheap. With the market full of offers like zero-percent financing, big cash back and low-payment leases, it's tough to remember a time when so many cars were so heavily incentivized. It might not be the best time to run out and add a weekend convertible to the household fleet, but if your lease is up or your warranty is expiring or you just plain...