From v1.1 of this plugin there is now a filter available for you to modify the price that is displayed. The filter is: wc_smart_sale_badge_price. This snippet should do what you’re needing:
add_filter( 'wc_smart_sale_badge_price', 'chantiqs_remove_sale_decimals', 10, 2 );
function chantiqs_remove_sale_decimals ( $saving_price, $product ) {
$saving_price = str_replace( '.00', '', $saving_price );
return $saving_price;
}
I haven’t tested that properly, but it should work for you. If you need further customisation then you will need to either do it yourself or hire a developer to help you out with it.
If this has helped you then please consider supporting continued development by leaving a review.
Cheers,
Hugh