Add a new setting: scale factor

[TheTisiboth]

The scale factor is meant to change for how much are the results computed. By default, there value are meant per $1 spent. But if the result is too small, we could multiply it, to have it per $1000 spent for example.
What should be the choices list ? And the default option ?
$1, $1000, $1000000, $1000000000 ?

[LorenHeyns]

Good to default to per million dollars spent.