My chart has four categories on the x-axis: Red, Blue, Green Yellow.
The y-axis is prices.

I used a line-chart to show the average price for each color. Now I want to
plot points on the same chart showing the actual prices for actual items, and
that way can tell at a glance how near the points tend to be to the "average
line".

So:

Item Color Price
Bob Red 2.20
Bill Red 4.50
Joe Blue 2.20
Dan Blue 2.20
Ann Green 3.20
Lynn Yellow 4.50

As you can see, several items may have the same color, and thus the same
x-value.
The number of items is much more than shown here--there are hundreds. If
only points in different series can share the same x-value, I will have to
use hundreds of series! And then the legend will be huge!

Is there a chart type that will work for me?