Bloodspore Thrinax was basically a bulk rare at the time of its release, though it has seen a ton of price movement in the wake of the printing of Atraxa, Praetor’s Voice. Bloodspore Thrinax was basically a bulk rare at the beginning of the week, and currently you would be lucky to find a copy for under $5.
Given that this card was only released in a Commander deck, most copies are sitting in the trade binder of people who purchased said deck, so there isn’t a lot most of us can do with this information. Though if this is the sort of card players are interested, I’m inclined to believe that other devour cards and cards with the evolve mechanic are worth exploring. Dragon Broodmother is a long time casual favorite that could see some growth. I think that Gyre Sage is an interesting penny stock. If Astral Cornucopia wasn’t in Commander 2016 I might be looking that way, though Gyre Sage does much the same thing.
There are plenty of non-foils out there due the card being from Gatecrash, though we’re talking about Commander specs. I like picking up some foil copies of this card, which is both a potentially large creature and mana generator. I’m no Commander genius, but both of those things seem to be what the format is about.