Отображать цену woocommerce в кнопке «Добавить в корзину»

add_filter( 'woocommerce_product_add_to_cart_text', 'your_slug_add_to_cart_text', 10, 2 );
function your_slug_add_to_cart_text( $text, $product ) {
    return sprintf( '%s - %s', $text,  strip_tags( wc_price( wc_get_price_to_display( $product ) ) ) );
}

Для страницы сведений о простых продуктах:

add_filter( 'woocommerce_product_single_add_to_cart_text', 'add_to_cart_price_for_simple_product', 20, 2 );
/**
 * For the detail page of simple products.
 */
function add_to_cart_price_for_simple_product( $button_text, $product ) {
    // For Simple products.
    if ( $product->is_type( 'simple' ) ) {
        $product_price = wc_price( wc_get_price_to_display( $product ) );
        return $button_text . ' - Just ' . strip_tags( $product_price );
    } else {
        $product_price = wc_price( wc_get_price_to_display( $product ) );
        return $button_text;
    }
}

add_action( 'woocommerce_single_product_summary', 'hide_product_simple_price', 8 );
/**
 * Hide the default price section on the detail page.
 */
function hide_product_simple_price() {
    global $product;

    if ( $product->is_type( 'simple' ) ) {
        ?>
        <style> .woocommerce .price, .woocommerce-page .price { display: none; } </style>
        <?php
    }
}