Filter the regular price of woocommerce products

Unfortunately the filter hook “woocommerce_get_regular_price” is not usable any more. There is another one alternative of that, you can use this below code to achieve your need.

function filter_woocommerce_get_regular_price( $price, $product ) { 

    // use $product->get_id() to get product ID
    // Do any custom logical action

    return $price; 
} 
add_filter( 'woocommerce_product_get_regular_price', 'filter_woocommerce_get_regular_price', 10, 2 );