Not so much if you're a PF Halfling, since they can get weapon familiarity and can knock it down to a free action reload as a racial trait, but that's neither here or there since we're talking 3.5, so agreed, should be purple for 3.5 games.
I say purple as slings (and staff slings) don't cost extra money to apply your strength bonus to, unlike almost every nonmagic bow out there, so if all you're going to use it for is as a backup ranged weapon, slings are a happy medium between bows and thrown weapons.