Baros from where Bar comes from
is based on Greek, for weight.

A bar, as in a pub or cafe, is where
transactions of exchange took place.

Barter is an extension of this.

Van Gogh, when he lived in Arles en
Provence, traded a painting for a baguette.

He also bartered his art for the room at
a hotel in which he lived.

Sad thing is, the hotelier sold up and
burned Van Gogh's paintings on leaving.