One way to get the min and max, create two calculated fields using the window_max and window_min functions. For example,
Make sure that the month field is on the level of detail shelf. Right click on each calculation on the view and select Compute Using-->month. Then, create a dual axis with these two fields. Right click on one of the axes and select Synchronize Axes. Finally, right click and edit the axis so that it is fixed to start at the minimum value.
Hope this helps a little bit!
That's amazing, thank you!
The next step was to simulate a bar so I added a reference line from the max value to 0 with a color fill and a reference line from the min value to 0 with a white reference line. This gave a look of a filled bar.
Last thing I am trying to do is add a mark on the scale with the last month's sales. Any insight into how to do this? Ideally it would be a shape mark.