Let's do some math here.
Currently, full-art lands from the original Zendikar are floating at around $1 per.
One BFZ fat pack is $40, and comes with 9 packs, a spindown, and 80 (supposedly) full-art basics.
Any given foil mythic is approximately 1 in 216, according to http://www.starcitygames.com/php/news/print.php?Article=17092
. This means that any one specific full-art nonbasic (not just the big money ones) is approximately 1 in (216 * 25 possible slots) 5400.
Of every 5,400 packs you open, statistically ONE of them will contain the full-art you want.
Because of that, these are going to be bonkers expensive and rare. I wouldn't be surprised to see well over three times to current going amount for the normal printing.
If you hold on to fat packs (which contain those 9 boosters, as well as $80 worth of full-art basics), you stand to make a very significant amount of money in a very short time. Hold on to the full arts if you want to double your cash. They're going to drop low, and rebound over time as people inevitably lose them and they are no longer in production.
And this isn't even accounting for any money rares this set produces. It's a good time to be a greedy fuck.