On your store, the 'Variable price display' alters what's shown on your product listings (as long as that product contains multiple variants with different costs - for example: red socks: $3, blue socks $3.50 etc):

To alter the 'Variable Price Display', from the store dashboard go to:
> Store Settings > Products > General

From within this page, under the heading 'Product Listings and Carousels', the 'Variable price display' can be altered:

The top box can be edited how you wish, but you must use the shortcodes in order for it to function ([lowest] for lowest price and [highest] for highest price):

The drop-down menu below is the recommended option as it changes the display for you:

(*Don't forget to click 'Save Changes' after making alterations*)