For anyone interested in the Preaching the Word commentary series, it is available for 50% off ($49 less than the Christmas sale) if you purchase it with an L7 library or base package.

Depending on your dynamic discount for the L7 library, you may be able to get some additional Starter library books for a very low cost or "free."
You would need a library in the cart, to be able to see the upgrade pricing. Sales apparently can offer upgrade pricing to anyone who purchased an L7 library in the last 30 days, so you may not need to purchase an additional library today.