Scourglass was once best known as "one of those garbage Wrath of God wannabes" during its time in Standard, though the card has always had a casual following. It slots right into white artifact decks, and that's exactly why it's seeing price growth right now.
Like a lot of price growth recently, this can be tied to Commander 2016. Specifically, Breya, Etherium Shaper is causing an increase in white artifact decks. A few copies of Scourglass can still be found for around $2, though this card will be a $5-6 item before long.
Notably, Scourglass is from Shards of Alara, which means that there are more foils than from other expansions of this era due to Alara block foil packs, though foils are in very low supply right now as well. If you're a Commander player in need, I would look to scoop up a cheaper non-foil copy today.