So I used all mine up hours ago in the ruin section w/ the tutorial (I was grinding a bit to cap my CP), I haven't seen it inside any of the shops; now I'm just outside Nautilus and I've got to ask :
 
Will I ever see any goddamn Deceptisol again!? It could be really useful on these stronger single mobs like the Wyverns - and I'm sure stuff I haven't even seen yet.

i usually get those types of items after a battle. i dont know how bad the drop rates are though.

...Deceptisol?
 
Wow.
 
I'm more a fan of Decepto-Bismol.

Every so often the merchandise in the stores increases, it might be there later. Deceptisol is meant to be rare because it leads to very easy battles. You should have saved it only for very tough battles.

The shroud items are not sold in shops until the very last chapter of the game.  Be very frugal with them.

You get 10 for fixing Vanilles pet robot later on.

" ...Deceptisol?  Wow.  I'm more a fan of Decepto-Bismol. "

" The shroud items are not sold in shops until the very last chapter of the game.  Be very frugal with them. "

" Every so often the merchandise in the stores increases, it might be there later. Deceptisol is meant to be rare because it leads to very easy battles. You should have saved it only for very tough battles. "

Ask your doctor if Deceptisol is right for you.

you'll get some from drops and chests throughout the game, but they are pretty rare.  I'd save them for when you need that -pre-emptive strike.  They're lovely when you are trying to 5-star some of the optional missions later on.

There are a few ways to get them. They are in some random chests throughout the game. You can buy them in a shop that you get very near the end of the game. The other way to get them is from battles. Their drop rate is greatly increased by getting zero stars.

Deceptisols, vaporize!

" You get 10 for fixing Vanilles pet robot later on. "

You get it in the story VERY late in the game, 40 hours in or so.

a shop called Eden's Pharmaceutical's, as Nekrosis said, very late in the game. They're really expensive though, 30,000 per