In a skill based system there is: skills.
Use military organization, propaganda, public speaking, bribery, etc for these things, depending on race and culture. Where barbarians might need to intimidate others in to their service, Romans need military organization (during the republics a legion was bought and paid for by its legate; who would set up a legion banner on a recruiting field in Rome during a special recruiting day in the year and his centurions and other officers would talk publican sons in to buying armor and take up a place in the legion for 20 years.)
As a GM you should wing it. People will not be eager to join such ventures, although paying upfront might convince many youngsters to go on adventure. Try poor areas, unless some culture has a streak of heroism.