The offering table does not have much use in the shoppe, and is freely available to you at the very start of the game.

It can be found outside of the shoppe, next to the front doors. Currently, the offering table's only purpose is to hold the Grilled Meat you make at the Grill using Raw Meat.

You can only place three offerings of cooked meat at a time, but you can hold the left mouse button while looking at the meat to reclaim them.

It is believed that any offerings placed on the table will be taken by Barbarians, thus preventing barbarian attacks from occurring. (Verified by the developer)