This came up in General, here's my suggestion.
For PC-class adventurers' hiring costs I'd suggest something like (Level squared)x10gp per month. This is in line with the relative power of the levels and the hiring costs in the DMG (eg 1st level Warriors are 6gp/month). Higher levels on dangerous missions would want a reasonable loot share too, 1/3 sounds reasonable.
Level squared x 10 gp =
1st: 10gp
2nd: 40gp
3rd: 90gp
4th: 160gp
5th: 250gp
6th: 360gp
7th: 490gp
8th: 640gp
9th: 810gp
10th: 1000gp
11th: 1210gp
12th: 1440gp
13th: 1690gp
14th: 1960gp
15th: 2250gp
I think characters over 15th would rarely if ever be available for hire in a regular campaign. If available to be hired, costs would be:
16th: 2560gp
17th: 2890gp
18th: 3240gp
19th: 3610gp
20th: 4000gp
For Epic level NPCs (in a _really_ high-powered game) continue the progression but multiply costs by 100gp instead of 10gp.
You can round the above numbers up or down for convenience. I think level-squared gives the best measure of relative power & thus expense across the board, although the CR system would suggest level 2 is x2 level 1, and thereafter +2 levels would be x2 cost, which leads to very high figures at upper levels. Certainly a level 20 Wizard is more powerful than 400 level 1 Wizards in most respects.
For PC-class adventurers' hiring costs I'd suggest something like (Level squared)x10gp per month. This is in line with the relative power of the levels and the hiring costs in the DMG (eg 1st level Warriors are 6gp/month). Higher levels on dangerous missions would want a reasonable loot share too, 1/3 sounds reasonable.
Level squared x 10 gp =
1st: 10gp
2nd: 40gp
3rd: 90gp
4th: 160gp
5th: 250gp
6th: 360gp
7th: 490gp
8th: 640gp
9th: 810gp
10th: 1000gp
11th: 1210gp
12th: 1440gp
13th: 1690gp
14th: 1960gp
15th: 2250gp
I think characters over 15th would rarely if ever be available for hire in a regular campaign. If available to be hired, costs would be:
16th: 2560gp
17th: 2890gp
18th: 3240gp
19th: 3610gp
20th: 4000gp
For Epic level NPCs (in a _really_ high-powered game) continue the progression but multiply costs by 100gp instead of 10gp.
You can round the above numbers up or down for convenience. I think level-squared gives the best measure of relative power & thus expense across the board, although the CR system would suggest level 2 is x2 level 1, and thereafter +2 levels would be x2 cost, which leads to very high figures at upper levels. Certainly a level 20 Wizard is more powerful than 400 level 1 Wizards in most respects.