My team has been tasked with defending a high value target on a lightning rail train. They're fairly certain that the train will be hit hard and are considering hiring mercenaries to flesh out the team.
Is there a standard rate I can quote them for a mercenary, or will I need to make one up?
Looking in the compendium, there do not seem to be rules for this. That said, if you're running Eberron, you might take a peek in the campaign book and see if there is something more specific to the setting. However, there are rules for pocket change and how much a major and minor purchase might cost that are pegged to the level of the character.
In general, I would consider hiring mercenaries (particularly a set who would make a difference fighting alongside adventurers) to be a major purchase, and probably a major purchase per PC. So if your characters are interested in hiring something like Level 1 mercenary thugs, I'd make that a Level 1 major purchase, 144gp.
The major/minor purchase table is in Mordenkainan's Magnificent Emporium, or can be found via DDI.
Mordenkainen's Magnificent Emporium has a section on Hirelings (starting page 136). Page 138 has a table of cost/day for each given level of hireling (from 15 @ level 1 to 125,000 @ level 30); the same page says a Mercenary is the standard Hireling rate x3 (meaning a level 1 Mercenary costs 45gp/day, and a level 30 Mercenary costs 375,000gp/day).
The Hireling section also instructs you how to stat out a Hireling. The start of the section also mentions that a Hireling may reduce the per-diem rate in exchange for a portion of the loot (at GM discretion).
It seems rather timid to just quote a price and have that be the end of it. Brian provided the numbers in another example if that's really the road you want to go down, but I'd urge you to think a bit harder about this.
Mercenaries do whatever they can to put coin in their pocket. Hiring more of them that the party can safely supervise might be a disaster waiting to happen. The mercs themselves might make off with the cargo if their pay seems too small. Up front payment might also not be the best option for paying the mercenaries as they then have nothing to make them stick around.
Role-playing the haggling could be an interesting way of broadcasting the caliber of men the party is dealing with. They might have to come to terms with the hiring of mercenaries being a necessary evil.
I know this isn't the answer you were looking for, but sometimes other people's insights can help us to rethink our game.
