For this trick you will need 2 magic items:

Jug of alchemy (uncommon)

Alchemical compendium (rare) (Tashas)

you use the jug to pour out the maximum amount of acid or poison (it doesn't matter which, both cost 12.5 GP) then you use the compendium to transmute it into a non - magical object, maybe some lockpicks, to escape prison, food for your adventuring party, dynamite, or if you are just looking for profit, a simple bag of gold.

if your DM lets you buy magic items, and you have the coin (and a lot of downtime) to spare, buy these.  fairly standard prices from how i play at least are 1 - 2k for an uncommon, and 5k ish for a rare. lets say it was 7k for both. if you constantly make bags of gold, or another easy to sell item, you can make back your money in about 600 days, also factoring in costs for living comfortably. this  is obviously a long time, so in most campaigns, this is not going to be anything more than a free* item printer.

in a chronologically long campaign, or one where you are constantly surrounded by treasure, but few shops, or even a sailing adventure where food is scarce, this might be the perfect item combo for you.

(if you just want to make money from this, you only need the alchemy jug, and someone who won't get suspicious of you constantly selling poison and acid to them. additionally, if you make the alchemy just with an artificer infusion, it is instant profit.

Maybe *a* lockpick (not plural), maybe a snack, maybe an explosive charge (singular, though most of them are over 12.5 gp).

Cannot make bags of gold -- you can make a bag, or you can make a gold piece. 

Cannot transmute magical items (says so in the magical item's description).

A set is not a single item. It is a set of items. 

Evtec Grumzanger III's Poison and Acid Emporium: Get your's today. Reasonable prices. Guaranteed effect. 

Disclaimer: Effects unknown. No guarantees. If used for illegal activities Evtec Grumzanger III's Poison and Acid Emporium (R) (TM) and affiliated Brand Franchices are in no way culpable or responsible.

I like this idea. I seems a lot of effort for comparatively little return on investment - and it's only improved by the fact that the local market for acid and/or poison will soon be exhausted. I imagine a general store full of random, dusty items, all priced at 12,5 gold piece. And a more than slightly tipsy store keeper, because the jug also produces beer. 

Really, he should have opened a bar instead. Getting the first 4 gallons of ale and the first gallon of wine for free should make for very good profit margins at a bar - without all the shenanigans.

Wouldn't this be easier to get a Cauldron of Plenty if you're just wanting to buy a rare item for eventual profit? You can make - and sell - 360 meals of stew a day. Even at a silver a meal, that's 36 gold a day. 

If you want more expensive items, be a Creation Bard. They can literally make things of eventually any value appear. They last hours and can be sold (just use a disguise so they aren't mad at you when it disappears). 

Or use Borrowed Knowledge for proficiency, get raw materials, and Fabricate what you want to sell : saving days or even months of work with just a 10-minutes of casting.

If you just want a convenient nonmagical object when you need one : invest 2 levels in Conjuration Wizard and just will it to exist, whenever you want, as often as you want.