Artisan encounters will always happen in a village, town or city - and for the most part, will be one-on-one meetings. Whereas most campaigns would see these as opportunities to blatantly sell players on committing themselves to an adventure scenario or quest, with the artisan begging the party to retrieve something, break into something, confront an enemy or some such, I perceive that none of those encounter tropes would be common or specific to artisans, as opposed to any person that might be met on the street. Artisans are not inclined to begin fights, organize themselves into gangs or see theft and melee as practical methods for expanding their reputation in the community. Artisans work at their trade: being makers and shop owners, working most hours each day in their own spaces, would have little time to frequent drinking establishments or chase people on the street begging for attention. As a result, most circumstances in which D&D "encounters" are thought to happen simply don't apply.
Characters and artisans would meet by chance, in the most obvious way: while purchasing things. A character moves from shop to shop, seeking bargains, the best equipment for the right price, equipment for the party (it may take two or three shops to find enough of a rare item) and so on. Some shop keepers talk; some do not. When a conversation is begun, it is done organically - a few words are spoken back and forth, both the character and the artisan find something they like about the other and the conversation begins. It is never about adventuring: it is about the exchange of thoughts, information, ideas. Moreover, it must be emphasized that the shopkeeper is as interested i what the character has to say as the reverse.
Each time the characters make a decision to do some shopping, when they pour over equipment lists (do not give an artisan encounter when a player knows what's wanted and specifically searches for one thing), ask the party if they appreciate that the hunting through shops in the market will take the whole morning or the whole afternoon. If an assent is given, "yes," have each player roll a d20 against their charisma. The player character that beats their charisma by the most will have an artisan encounter, by themselves (sternly inform the other characters not to give advice, though they can comment). If two or more characters tie, either roll it off or prepare to give more than one artisan encounter.
Artisan encounters may be brief, depending on the character. When they have gone long enough, have another customer require the artisan's attention, so that the conversation is cut off that day. Obviously, the player can end the conversation at any time.
Artisan-Character discussions are not set; however, the following topics will be typical, any of which can be used to gain the artisans favor (don't expect immediate bargains - but after 2-5 return visits a given artisan will 'save back' special items or may give away small items for free), which may mean opportunities for further exchanges. Presume that all artisan-character conversations are positive (charisma check was made). Artisans will no do things for the player, however, if asked, nor with the artisan ask anything of the player.
Subjects include the list below; there is no need to stick to any one subject or to cover any subject that doesn't seem relevant to the player's choice of dialogue. The artisan will:
- be interested in seeing anything the characters are carrying that is visually unusual, wishing to know where it has come from; in general, the artisan will be curious to know where the character has come from or what the character is doing in town.
- be interested in showing off things of his or her own creation, not to sell it but to discuss how a particular thing was made.
- express personal opinions on the state of the community, the town or city, the region or the whole country, being either disgruntled at the state of affairs, happy with them or doubtful if such will continue. The artisan will not commit treason but may express a number of blatantly uncomfortable viewpoints. Resist having the artisan make personal comments about the player character - race, creed, whatever - as the artisan still sees this person as a potential or paying customer.
- give a positive opinion or suggestion about where else the character could look, something else the character should buy, something the character ought to see in town (because it is interesting) or worthwhile warning about a particular road or place in the area.
- describe something the artisan did once that was very brave, particularly when speaking to an obvious fighter; the artisan will probably be looking for respect from the fighter while in turn offering it.
- describe the effort he or she has taken to get the shop in order, to survive the economic circumstances and perhaps tell a tale or two about some difficulty that was overcome ("we had a fire two years ago, we're still coming back from it").
- draw the character's attention to the object they've chosen to buy as not one of the best in the shop, offering a better one in its stead (perhaps with a +1 bonus to save against random destruction).
- discreetly express approval for the character's attractiveness or personality, flirting politely.
- offer his or her name for the player to use in seeking out good accommodations or some other minor benefit (depending on how well the character plays the conversation).
- warn the player about a local crime the player may be breaking without knowing it (carrying banned weapons, wearing a disallowed color, showing too much skin, etcetera), or any other thing the player might want to avoid doing in the area.
- thank the player for coming to his or her shop, wishing the player the best in future endeavors.
- make/tell a joke.
- offer a wager.