I talk about running a D&D business a lot because my players are always involved in some moneymaking scheme above and beyond the usual adventuring. I’ve tried the 5e rules on my group’s pizza joints, designer tabards, and bishoprics, and I’ve cobbled several sets of business rules together, and I haven’t really been happy with any of them. Either they’re too profitable or not profitable enough, and they always add a layer of bookkeeping. I think I’ve got a solution that cuts the Gordian knot.
Business, fiefs, and other investments don’t give you money, they pay your lifestyle expenses.
Investments (businesses, feifs, etc) pay for your lifestyle expenses. Cost is at the DM’s discretion: 1000 gp and 1 month per 1 gp daily allowance is a good starting point. Optional: roll a monthly random encounter check. An encounter means a threat to your investment which might reduce or raise your income.
I like 5e’s lifestyle expenses, although I don’t recall making my players pay them that regularly. Doing the accounts is a little bookkeeping task that’s fiddly enough that it often goes unremembered. What if owning a business (or feif or temple) is a way of buying your way out of this chore?
How much should it cost to invest in a business? As a rule of thumb, say that it will pay for itself in about three years (say 1000 days). That means that a shop that will pay you a modest lifestyle (1gp a day) costs around 1000 gp. A barony that will pay for a low-end aristocratic lifestyle (10gp) is worth 10,000 gp. Let’s throw in a time cost too: a month of downtime per 1000 GP. That means that building a baronial castle will take about a year.
Adjust this ballpark price based on circumstance and player cleverness. A fief with a mouldering castle might be given free as treasure, but it might still take 50% of the normal downtime and cash to get it running. An ice-cream shop in Al-Qadim will be more profitable than one in Icewind Dale.
Upgrading a business is easy – pay 1000 gp and 1 month, more or less, to add 1 gp to your living expenses, or if you need 1000 gp in a hurry, do the reverse (no downtime required).
Every business has growing pains
Here’s one bit of optional bookkeeping: every month, roll a random encounter check for the business/fief (17-20 on a d20, or 6 on a d6). An encounter means an event that requires the players’ attention: bandits move into their fief, for instance. If the players don’t deal with the situation, their daily income goes down by, say, 1 gp. If they deal with it adequately (kill the bandits) the problem goes away. If they deal with it cleverly (convince the bandits to join the militia) their living allowance goes up by the same amount.
I recognize that this monthly die roll reintroduces some of the complexity I removed. But it’s less like bookkeeping and more like a source of adventure hooks.