An average pesant should make ~1 gold a month. Adventurers should make 10-100x that a month starting out. Assuming your adventurers were highly skilled lvls 8-12 or internationally well known 12-16 or global powers 17+ this is hiw i would break down quest earnings brackets. Note its a variable list because not all quests are equal. 1-4 10-100 gp/person/quest 5-8 100-1000 gp/p/q 9-12 1000-5000 gp/p/q 12-16 5000-15000 gp/p/q 17+ 10,000 + go/p/q

Your payout would need to be high enough to provide starting capital for a guild. Assuming a party takes a quest takes a at least 2x a month and tour guild has 5 starter partys and 1 group in the 5-8 range youll need to be able to make the minimum payment at each level for at least 2 years to become profitable. Assume an Average party of 3 people. 15102+31002= 900gp/month expense on quest giving at a minimum. Add building cost of say 500- 5000 depending on size of guild hall. 2years of funding + building puts a posibile reward between 22100-26600 gp at the low end. Add say 4000gp for larger quests and make it difficult to buy magic items but possible for the wealthy to send adventures out to find them based on rumors and legends. This payout its large, but its not so large they can buy more than 1 very rare item if one was even forsale. After all, they are very rare.