Saw this on another board: If you buy The Marine and The Sentinel Blu-rays together, you get an additional $3 off (both for $36, even less if you have the Amazon 10% discount thing as well).
I can't remember the last time I payed $20 for a DVD (about the only pricey DVD that springs to mind is when I just had to have the Criterion Robocop back when it was released and I paid $35, only to have to exchange it, by mail no less, for one that wasn't scratched and unplayable). Keep in mind that was many years ago.
I pay $13 or $14 when they're on sale release week or wait a while until they drop the price or appear online for sale. Evem Batman Begins, I scored the 2-discer online cheaper than I could find the 1-disc when it was released. Otherwise, I avoid the overpriced 2-disc WB releases since other companies don't charge you nearly double to get the extras. Back when the Matrix sequels first hit DVD they were 2-discers (before the time of choosing between 1-disc and 2-disc versions came), and I picked those up for around $13. The two-tier pricing of new releases today stinks.
I'd like to hear real confirmation about TFE thing. I'd have to buy it and another title to get free shipping though.
Although now that you mention it, many of those titles, incuding the few I'm interested in (like AvP or FF, or to a lesser extent (depending on your take on it) X-3) are B-movie caliber, but flicks I got some entertainment out of nonetheless.