Well, Lulu is having another sale. 35% off today only (and yesterday too, but they're not real timely about sending me their coupon codes). Use BLIZZARDS305 at checkout.
So, this means they are losing money on every PDF purchase, since their royalty is only 20% usually, and is currently 10% til mid-January, and the base fee charged is on each PDF sale is just 99 cents. The authors (namely, moi) don't see any price changes on these sales, so Lulu is eating all that. They must have some hefty markups on the base cost for print books for these sales to be remotely profitable, because print royalties are also 20%.
How does this make any business sense? No idea. I'm guessing PDF sales are a very tiny part of their business and they just ignore the losses.