If you like to change the product price color without change the CSS styles, you can made it easier with the “Woo Product Price Styler” plugin.
How to change the price font size and color:
The path for the plugin option is in the WooCommerce settings in the Products tab. There is the option “Product Price Settings” where you can easy apply the price styles.
There is separate styles for the Regular and the Sale price.
The plugin has 4 templates for every price size in a dropdown menu. You can choose the template for your theme from small, medium, big, wide.
Also, there is 2 color palletes where you have the possibility to choose unlimited colors regarding your theme.