Show MSRP Price in WooCommerce WP-Lister for Amazon

If you use the WP Lister for Amazon plugin you are able to set a custom MSRP price for products. But these do not show as stroke trough price if you enter a regular or sale price.

Add the below code into your functions.php and the regular price will always show the MSRP price if set.

/**
Change on sale to true if MSRP is set, otherwise price only shows regular
**/
add_filter( 'woocommerce_product_is_on_sale', 'we_msrp_on_sale', 10, 1);
function we_msrp_on_sale($onsale) {

    global $product;
    if(!$product) {
        return $onsale;
    }

    $rrp = get_post_meta( $product->get_id(), '_msrp_price', true );
    if($rrp) {
        $price = $product->get_regular_price();
        $onsale = true;
    }

    $variable_rrp = get_post_meta( $product->get_id(), 'variable_msrp', true );
    if($variable_rrp) {
        $price = $variable_rrp;
        $onsale = true;
    }

    return $onsale;
}

/**
Sale price will be regular price if msrp is set
**/
add_filter( 'woocommerce_product_get_sale_price', 'we_msrp_sale_price', 10, 1);
function we_msrp_sale_price($price) {
    global $product;
    if(!$product) {
        return $price;
    }

    $rrp = get_post_meta( $product->get_id(), '_msrp_price', true );
    if($rrp) {
        $price = $product->get_regular_price();
    }

    $variable_rrp = get_post_meta( $product->get_id(), 'variable_msrp', true );
    if($variable_rrp) {
        $price = $variable_rrp;
    }

    return $price;
}

/**

**/
add_filter( 'woocommerce_product_get_regular_price', 'we_msrp_price', 10, 1);
function we_msrp_price($price) {

    global $product;
    if(!$product) {
        return $price;
    }

    $rrp = get_post_meta( $product->get_id(), '_msrp_price', true );
    if($rrp) {
        $price = $rrp;
    }

    $variable_rrp = get_post_meta( $product->get_id(), 'variable_msrp', true );
    if($variable_rrp) {
        $price = $variable_rrp;
    }

    return $price;
}