The idea with roleplay is that you can make up your own job. Be a hobo, and dance for cash, or sing in the streets, using /s and /me commands. Sell pasta, sell potatos, sell anything you can think of.
Alternatively provide a service, if you're fireman, do car wash with extinguisher or fire truck, be a mechanic, fix peoples cars, or collect players cars and rent them out.
To contact people without money for /ad, you can use /s to shout when driving past players, hand out leaflets with /me . Send SMS messages to advertise with /getphone and /sms.