Probably depends on your industry and implementation. I'm new to the workforce so I don't have a lot of experience with it, but I've seen some comments on reddit over the years with people getting piddly little bonuses (tens of dollars) and having management tell them they should be happy they got anything. The workers would have preferred getting nothing and it was a morale killer.

I don't know what good levels are. Maybe think of it in terms of % of salary for the median employee? $30 wouldn't feel genuine to anybody, especially if it looks like people at the top aren't cutting back. $250 for a developer making $175,000/year makes a much smaller difference than for support staff earning $40,000/year.

Another thing to consider - if things are tight and you don't already have a holiday bonus, a certificate to get a ham, turkey, or meat and cheese tray at a nearby grocery store would seem more genuine than a piddly $30 cash bonus. Of course switching from ~250/year bonus to a ham will be a morale killer.