styker said:
what do you do when a players want to stay in a city taking money selling his teleport service or when the cleric group sell his services to ressuscitate other adventurers? how much money do you let then win? and how much times?
Actually, I just let the Laws of Supply and Demand take over.
I do the same thing with goods and services that the PCs want to purchase (as opposed to want to sell).
For example, the PCs in a recent campaign needed pearls to Identify items. So, they went on an almost daily basis to the local jeweler asking if he had pearls. The chances were low, so the jeweler said "Not today" nearly every day for several weeks. Then one day, I made the roll and the jeweler said "I got a new shipment in. I have 30 pearls. How many do you want?". The PCs took most of them (26 I think at 100 GP a pop and that took up most of their ready coin) simply because they suspected that if they did not, he might sell the rest of them and it might be many more weeks before more pearls were again available (it was in fairly far inland city in this case).
Do the same thing with the PC goods and services.
PC: day one "Does anyone come in to purchase our goods and/or services today?"
DM: rolls dice "No, but 3 little old ladies and a stevedore come in to see what you have. All of them are window shopping though."
PC: day two "Does anyone come in to purchase our goods and/or services today?"
DM: rolls dice "No, in fact, nobody comes into the shop at all today."
PC: day three "Does anyone come in to purchase our goods and/or services today?"
DM: rolls dice "No, but a gnome comes in asking if you have the lost Heirloom of Drasada."
Remember, not everyone has 1000 GP or more to buy magical goods or services. In fact, 99% of the population cannot afford such things and the other 1% has their own contacts already and/or also only make such purchases a few times a year at most (if that often), even in a city.
Now, I would carefully explain this to the players before they actually try to set up shop. One possibility is for the PCs to hire someone as an intermediary broker. This NPC sets up shop for the PCs and when customers come in, he sells the goods or services for the PCs. Course, if it is a spell that needs casting, he will have to inform the PCs that a client is available and they will have to stop adventuring in order to come back and cast the spell.
The odds would be slim though. On a D20, I would require something like:
Potion: 18+ on first roll, spell level * 5 or higher on second roll.
Cast spell: 19+ on first roll, spell level * 2 or higher on second roll.
Scroll: 20 on first roll, spell level * 3 or higher on second roll.
Craft other item: 20 on first roll, caster level or higher on second roll.
every single day. If the roll is made, a customer comes in requesting the item or spell. This would be a single roll, so if a 20 is rolled, I would roll randomly to see if the customer wants a potion, scroll, spell, or item. If so, I would then roll to determine the level of the good or service. So some days, a customer comes in wanting a 7th level spell cast and the PCs are too low level to do that.
And actually, I would probably set up a chart for the second roll so that the odds of lower level spells/items are requested at a higher percentage chance for the second rolls (e.g. 20% chance first level, 15% chance levels two and three, 10% chance levels four through seven, 5% chance levels eight and nine).
The PCs might manage to sell a potion once per week and sell an item/spell once per month this way. Maybe. I would still have them go on quests to gather the supplies needed to craft any item though (even scrolls and potions).
This allows them to be successful doing this, but not overly successful. Plus, it forces them to adventure, just to keep their business running.
PS. Do not forget expenses of running a business. For example, leasing of the shop both front area for customers and possibly back area for crafting goods (if they do more than just sell spells), paying the NPC broker, storing goods and materials, advertising, protection costs against thieves and vandals, including making sure the NPC broker is trustworthy, etc.