How much profit can a low-level caster make by offering Mending as a service during downtime?

Question

How much profit can a low-level caster make by offering Mending as a service during downtime?

A low-level spellcaster without tool proficiencies would like to earn some money in downtime. How much could they typically earn per month by using the Mending cantrip to repair assorted items?

Mending:

This spell repairs a single break or tear in an object you touch, such as a broken chain link, two halves of a broken key, a torn cloak, or a leaking wineskin. As long as the break or tear is no larger than 1 foot in any dimension, you mend it, leaving no trace of the former damage.

Answer 1

With the Work Downtime Activity, Up to Comfortable Lifestyle + 25 gp per week

This sounds a lot like the Work downtime activity from Xanathar’s Guide to Everything, and roughly the same type of activity as using tools, but substituting magic with the tools. By using this downtime activity, you can support earn enough to maintain a Poor to Comfortable Lifestyle for a given week, with exceptional rolls gaining an extra 25gp on top of the Comfortable Lifestyle. The amount you earn in a week depends on a skill check made to represent the type of work you do. A repair shop would typically be represented by the use of an Intelligence check + tool proficiency.

Now, since your spellcaster is not using tools, the above does not strictly apply. But given the similarities with the type of work being done, I would allow a check based on your spellcasting ability. Possibly include the proficiency bonus, similar to a spell attack roll and other similar spellcasting checks.

However, mending can generally only make small repairs. That means the range of services you can offer is smaller what you can do with regular old manual labor, and so one can expect a laborer whose talents are limited to this spell to have difficulty earning as much as someone that can use tools. Therfore, it may be reasonable to apply Disadvantage to the check. Unless you can come up with other magical supplements to your mending business.

Answer 2

It's totally up to the DM, but probably not a whole lot

The best citation I know of for this is from the Player's Handbook:

Spellcasting Services

People who are able to cast spells don't fall into the category of ordinary hirelings. It might be possible to find someone willing to cast a spell in exchange for coin or favors, but it is rarely easy and no established pay rates exist. As a rule, the higher the level of the desired spell, the harder it is to find someone who can cast it and the more it costs.

Hiring someone to cast a relatively common spell of 1st or 2nd level, such as cure wounds or identify, is easy enough in a city or town, and might cost 10 to 50 gold pieces (plus the cost of any expensive material components). (PHB, Chapter 5: Equipment, Expenses, Spellcasting Services)

So the best guidance this gives in terms of an actual money value of such a service is less than 10 gold pieces. But even 9 gold pieces per casting is a lot! It's enough to finance a wealthy lifestyle with just one task every other day (also drawn from the same section of the PHB, under Lifestyle Expenses).

And, I would argue, it's too much for this service. The biggest issue is that Mending is a cantrip available to many classes (Bards, Clerics, Druids, Sorcerers, Wizards, and Artificers; more, if people want to take relevant feats).

Services that are easy to find are less expensive than rarer ones, and there is a real chance of being undercut on pricing by someone else who knows the cantrip. It's probably not realistic to think that your player's character could command 9 gold per casting-- that would mean anyone who knew that cantrip would be wealthy, which would suggest that a lot of people would make the effort to learn it. And if it's widely known then at least some people will be willing to provide the service for less.

Finally, the starting wealth for the classes with easy, automatic access to Mending is not exorbitant, which suggests that this should not be a huge moneymaker. It's as high as 5d4 * 10 gold pieces at the top for Bards and Clerics, as low as 3d4 * 10 gold pieces for Sorcerers. It's only 2d4 * 10 gold pieces for Druids, but they might not be as focused on money as other classes.

---

14 silver pieces to 7 gold pieces per day is reasonable as a guideline if you want variety in earnings, or 1 gold piece per day if you want it to be steady

The range is drawn from the possible outcomes listed in Xanathar's Guide to Everything (Chapter 2: Downtime Revisited, Example Downtime Activities, Work). I won't reproduce the table, but those are the extreme ranges of results. The single gold piece per day is drawn from the PHB (Chapter 8: Adventuring, Between Adventures, Downtime Activities, Practicing a Profession).

---

Make sure you don't let the tail wag the dog

Wealth has an odd representation in D&D 5e, and while players often enjoy earning money (especially in creative ways) their ability to do so doesn't really drive much in the game.

The only downtime the PCs will have available is what the DM explicitly grants to them. The amount of money that people have to spend on magical mending is totally up to the DM. The major determining factor in how much money a PC can make during downtime is more a function of how much money the DM wants them to have than it is a function of how valuable the PC's service is. It is entirely sensible (though definitely not necessary) for the DM to make a judgment more on that basis than on how much a real tradesperson in that setting might charge or earn.

Answer 3

In Xanathar's Guide to Everything, the extensive Downtime Revisited section offers various options for making (or spending) money during your downtime. The only one that seems relevant to this is "Work", which usually means physical labor, performing at taverns, or other such jobs, with the resulting income determined by a relevant ability roll (applying proficiency for an appropriate skill or tool set, as usual). The roll result is compared to a table given in the book to find out how much you make, but generally you make only living expenses for the week unless your roll is over a 20.

Offering spellcasting services doesn't seem to fit cleanly within that structure, but only in the sense that spellcasting doesn't have a clear skill associated with it. However, if we assume that you can be considered proficient with your spellcasting, then it's reasonable to roll your spellcasting ability score plus proficiency (which is functionally the same as making a spell attack roll).

Alternatively, a DM might decide you need to make a Charisma(Persuasion) roll instead, representing not job performance (which is largely dictated by the fixed effects of the spells you know), but convincing people to buy the services you're offering.