The Vita version will go <$20. PS4 <$30. Just wait..
To be fair, Toukiden is one of the best experiences I've had on the Vita. I think the amount of content is both vast and enjoyable enough to make the price tag worth it, even at full price, much less the sale prices now.
If anyone is on the fence about it, I highly recommend it. If you enjoyed Monster Hunter or Soul Sacrifice and have an open mind, then Toukiden is very enjoyable. Its combat is much faster than Monster Hunter, albeit less deep, and its narrative is not as unique or as engrossing as Soul Sacrifice's, but still contains a great story for a hunting game.
Also, the AI partners in this game is among the best you'll see in any hunting game. They don't require you to help them all the time and they'll even make things more convenient for you by actually helping you in battle and absorbing monster souls/parts. Online component also works quite well. I've played with my friends a lot and we rarely run into problems unless it's one of our internet connections logging us off or the Vita having problems itself.
All in all, very solid game. Highly recommended. I regard it as one of the Vita's best.