Back in October 2016, Insidious Will was a $0.50 card that was buylisting for close to its retail price. People were actually pretty excited about this card. Even though it costs 4 mana for effects that typically cost only 2 or 3 mana, the versatility of this card seemed to make it worth it. With Baral, Chief of Compliance looking like he’d be a big part of Standard, it seemed to some people that Insidious Will was going to be at least a $1 or $2 card. This never happened, although Baral, who makes Instants and Sorceries you cast cost 1 less mana, is very good. In fact, Baral is probably going to be tied to this card’s long term value.
Two of its effect choices are Redirect and Twincast. These are cards that each cost 2 mana, being able to choose seems worth an extra price. The third choice is essentially Cancel, which is 3 mana as a straight counterspell. But, wouldn’t having these choices in a control deck be a nice thing to have, even just as a one-of out of the sideboard?
The answer is yes... in Baral, Chief of Compliance EDH decks. Baral has become quite a force in the growing 1v1 Commander scene, thanks to Magic Online adopting the format as a competitive league. It’s clear that most demand for Insidious Will comes from EDH players. While Baral is hardly the only Commander that plays this versatile 4-mana instant, he’s definitely the one who’s added this spell to his library the most.
So, what’s made Insidious Will a bulk rare? It simply never found relevance in the Standard format of the day. It would pop up in the odd Blue/Black Control list. Some people considered trying to use Insidious Will to copy Approach of the Second Sun for a quick instant win, but that didn't work because the second copy of Approach of the Second Sun had to be cast from the hand.
Long term, though, cards like Insidious Will easily surpass $2. Foils of this card will definitely not be less than $2 forever, either. The price of this card is always competitive, meaning that the market price of the card has historically been very close to the median price. That's good news for this card's future, as supply is barely meeting demand.
When it comes to the anatomy of this bulk rare, Insidious Will was a card released at a time where its value simply wouldn't be realized. One copy per Commander player coming off the market at a time simply won't drive the price. This is a card that you want in foil if you’re looking to cash in on it in the long term. But, as far as people who just want it to play with, it’s definitely well worth spending a couple hard earned dimes on to add it to your collection.