A busser cleans the tables of dirty dishes, sweeps the floor, dumps the garbage.
The hostess takes people to the table and gives them the menu, sometimes if its busy she will also bring them their drinks.
They rarely get the tips unless the retaurant takes all tips and divides it between everyone at the end of the day.
Grocery store is union they all get a good salary eventually but you have to get into a slot and that is hard. A waitress can make a lot of money in tips on a good night.