Whether you like it or not, and whether you think it’s a fad that will pass, Frontier is causing significant market movement. The more than doubling of the price of Jace, Vryn’s Prodigy is clear evidence of that. Hangarback Walker is a card that sees fringe play in other formats, though is currently ticking up in value likely due in no small part to being prominently featured in Frontier Ensoul Artifact decks.
Hangarback Walker was a $2 card that has now moved into $4 territory and is on a path to the $5-6 range. Being from Magic Origins means that the initial supply of the card is relatively low as compared to other Frontier rares, though it notably was printed in an Event Deck. It’s entirely possible that Hangarback Walk trends towards $10, though I would be surprised if it went much beyond that. There are still over 200 listings on TCGPlayer, and I would only be buying if I could find some $2-3 copies or was looking for a set to play with.
Given the price movement on Hangarback Walker, I would be investigating the viability of Goblin Rabblemaster in Modern. Rabblemaster also has a second printing given its promo version, but held a $15+ price point despite this for a while when it was Standard legal. At just over $2, that could be a stellar acquisition.