Logically, I think that the Watchers' Council not only should have given Buffy (and all other Slayers going back centuries) a living stipend of some kind, but they should have WANTED to. I mean, every minute Buffy spends earning a living toiling at the DMP is a minute that she isn't out patrolling, destroying vampires, combatting evil, etc... Slayers would be much more effective if they had fewer mundane responsibilities and worries to distract them.... plus, since the WC is a bunch of control freaks, having the Slayer be dependent on them for her very food and shelter would be a very effective too; for domination...