So I figure that an alchemist can probably make some good business. Every preparation is good for a few hours at least - probably more than just a few. Say, 8 hours for the sort of preparation that most runners would be looking for - a Potency 4 preparation. The cost to the person making the alchemical preparation is however much the lynchpin cost plus however much the drams used cost, assuming they used drams (and they should, since they really don't want to be taking lots of drain that would prevent them from making the short-lived alchemical preparations that they're selling for a living). So let's assume 5 drams spent per preparation. That's 100 nuyen. Object resistance is no concern, so literally anything can be the lynchpin, so the cost of that is going to be anything from totally extravagant to completely negligible depending on the alchemist.

So assuming a base cost of 20 nuyen per Potency and all spells cast at Force 1 (which is completely ignored because you are setting the limit with drams), what would be a reasonable market cost for these preparations? 200N/Potency, plus the cost of any exotic lynchpins used? Professional alchemists are probably not going to want to endanger their business by selling preparations that contain combat spells, so that's probably black market only. For that matter, much of their business is probably in preparations made to cure disease or heal injuries. But even so.

Anyone have any thoughts here?

...this information should really have been included in Street Grimoire. The book outright SAYS that Talismongers sell Alchemical Preparations, and then fails to list a standard market price for them.

On a tangentially related note, unless I am just misreading these rules, it seems it is always better to do alchemy with reagents than it is to do it without. Cast the spell at Force 1, set the Limit with reagents. You roll your Magic + Alchemy against a single opposed die, and the Potency (and therefore the duration) is equal to your net hits. Which is what I assume any professional alchemist does when making preparations for customers in her shop.

Yes and No.

You can go making your preparations at Force 1 and jack up the hits at creation using reagents to get a good potency which gives you a bit longer shelf life.

Just remember when the preparation activates, it rolls Force + Potency [Force] as though its spell was just cast.
Reagents do not change the limit for the preparation’s activation; they only increase potency during creation.
So if you went with a Force 1 spell as your base, you would still only be keeping a few hits for its end effect.
The best solution in this case is use spells that are not heavily hit-dependant for their final effect.

Aaah, gotcha. So for hit-dependent spells (Increase Reflexes, Increase Strength, whatever else), you'd need at least Force 4 as the base, though you might set the limit higher than that with reagents. Okay then.

Something between 5 and 10000 ¥, depending on the one selling.

But I don’t think that there will be a black or grey market for working and reliable alchemical/charms. And legal shop will most likely go through great lengths to protect them self from legal persecution.

Why do you think that? I can easily see runners or others wanting these sort of things. I can see the magicians making them being leery of creating a material link to themselves and then selling it to nefarious customers but money outweighs common sense in many situations and this is likely no exception.

The alchemical preparation carries the astral signature of the alchemist that created it.

With the right metamagic, I believe you can remove or scramble this. But yeah. I figure this is a very good reason why most alchemists would not be willing to sell preparations that could be used for combat magic; because the magical forensics team could trace that back to the alchemist who sold it.

With the right metamagic one could mask it, but when you are capable to reliable mask your charms (in SR5) you are normally unaffordable, for runners.
The signature problem alone could be manageable but you cannot stock, export or import charms. You can only prepare them on demand, which is the greatest problem I think.

An organization could make it work, keeping the alchemists (for teamwork tests) hidden. But they have to invest a good sum in “holding” professional alchemists, maintaining a secure/secret workshop, a fast and obscure distribution network and have to pay for protection (law and mob).
And at this point for runners it becomes cheaper to just hire a mage.

How exactly will you be using the alchemist's preparation>
Command requires he come with you as he needs LOS.
Next person to touch it: that leaves out most offensive spells unless of course you're into having a fireball explode around you.
Time....when do plans ever work out like the should in shadowrun...ticking clock just adds to the likelihood something goes wrong.

My support mage uses alchemy primary with contact trigger.
And I think if someone gives away charms, contact trigger or advance contact triggers, like timed anchored version, will be thing. (SG p. 219)
If you have a lot of money to burn, maybe Detection Spell + Anchored Spell as trigger, but that will cost you, a lot. Something like contact + anchored + detection spell (detect enemy) + offensive spell. The Detection spell must be quickened and that costs karma / a shit lot of money.

But you don’t want to combine offensive spells and alchemy, indirect AOE is the exception. With its double cast double resist, offensive alchemy is too ineffective.