But can they even get it legally?
Well, black powder recipes vary but most of the ingredients are fairly common.
However, if black powder itself were illegal because of its danger to the "wizardy" upper class...possession of it might be as illegal as poison.
I would think the average NPC would choose to pick up and use a sword rather than use a strange (alchemical) weapon that might blow up in their face.
Well, in a world where "spark" is required, and you're a dude who is the same general physical and intellectual type as Morpheus the Archmage of Dream...but you don't have the "spark?"
You might find alchemy
a lot more your speed than hefting a sword.
I know one player who prefers to play the same "type of wizard," always.
Is his name "Russ?" My buddy has played variations on the same wizard for the past 20 years (with brief interruptions for things like the odd Paladin), and his PCs' spell-lists would probably be immediately identifiable to people like Thanee. There may not be more than a 5% variance in them over the years.
It didn't bother me to much because I didn't mind his character being some extraplanar human from another time and world that just popped into the campaign world due to a miscast teleport spell. But in a campaign with a need for that heredity "spark," such an outsider might not be possible. How would you include such a character in a "magical spark" campaign? (I'm truly asking; Id like to hear your ideas on this matter.)
"Spark" can have a lot of origins- artificial or natural, singular or multiple- which could be more common in the PC's world of origin. He (and the people of his world) could also simply be unaware of the "spark" requirement...those with it are somehow simply called to it, subconsciously.
"Spark" could be a simple mutation/variance in the gene codes. Like the fluff from the Sorcerer, it could be the result of long-ago miscegenation with beings who are innately magical- Demons and other outsiders, Fey, dragonkin...you get the picture.
Perhaps the "spark" derives from a pact that someone in the family (even the PC) made with otherplanar intelligences. That worked for writers like Moorcock and the Binder & Warlock's fluff-writers.
If your campaign world is secretly a post-apocalyptic one in which high-tech societies fell, being replaced with resurgent magic (see Brook's Shanarra and RIFTS, for instance), the "spark" for some forms of "magic" like psionics could even be the result of bioengineering or nanotech.
It could be that the teleport accident itself is the source of this PC's "spark."
Perhaps, like Kal-el traveling from doomed Krypton to Earth (or that one episode of Sliders), the rules of his world of origin are different enough that, while mundane in his homeworld, he is magical in this one. This kind of "spark" has all kinds of interesting RP and mechanical implications- there may be some planes in which this guy's magic simply doesn't work...
while everyone else's does. And vice versa!