In order to get into the holiday spirit, today's investment pick is Greed (specifically the original Legends printing and the 7th Edition FOIL printing).
The maturation of the game, since this was first printed, has shown that this effect is a very powerful one, prone to prohibitive casting costs and major sacrifices (see Griselbrand and Necropotence). Nothing strictly better than Greed has been yet printed. It allows you to use the draw as you need, without a game-state drawback. It's relatively mono-colored (as compared to cards that achieve a similar effect). And most notably:
This saw a reprint, with new art, in the Commander 2013 set. The supply of those products has started evaporating and reprints therein have largely rebounded by now. Greed saw its introduction to a vast new generation of Magic players, all of those added since the 2011-2013 "Renaissance", all of whom now want the most-pimped version of the card. So a new channel of casual demand (especially Commander demand) was foisted onto this card, so the "best" versions became sought after like never before. In addition to the original Legends printing, there is only one FOIL copy of this card, and it's from 7th Edition: the first base set to include FOILs, a set that sees a very high FOIL multipliers across the board. Sure enough, the 7th Edition FOIL is showing bottom-up pressure that has yet to cause a spike.
So, in addition to snagging some original black-bordered Greeds at $4.00 or under, go deep on 7th Edition FOILs at $10.00 or under (if you can find them... the spike is imminent).