I think that places where I live (Norway) have to take back the bottles that they sell in their store - even gas stations - but the only place I see the machines is at the grocery stores. (Grocery stores are generally smaller but more convenient than they were in the US).

And it is by item - less money for small bottles (single serve soda, for example) and more money for larger bottles (1L of soda or juice). Aluminum is similar.