Code to hide the original price and display only the discounted price for the BOGO gift item(Old bogo) - By WebToffee (Smart Coupon For WooCommerce Plugin)

functions.php

<?php //Do not copy this line of code 
add_filter( 'woocommerce_cart_item_subtotal', 'wbte_sc_ctm_alter_cart_item_price', 1001, 2 );

add_filter( 'woocommerce_cart_item_price', function( $price, $cart_item ) {
	return wbte_sc_ctm_alter_cart_item_price( $price, $cart_item, false );
}, 11, 2 );

function wbte_sc_ctm_alter_cart_item_price( $price, $cart_item, $is_total = true )
{
	$out = $price;

	if ( 
		class_exists( 'Wt_Smart_Coupon_Giveaway_Product_Public' ) 
		&& class_exists( 'Wt_Smart_Coupon_Giveaway_Product' )
		&& method_exists( 'Wt_Smart_Coupon_Giveaway_Product_Public', 'is_a_free_item' )
		&& method_exists( 'Wt_Smart_Coupon_Giveaway_Product', 'get_product_price' )
		&& method_exists( 'Wt_Smart_Coupon_Giveaway_Product', 'get_available_discount_for_giveaway_product' )
		&& method_exists( 'Wt_Smart_Coupon_Giveaway_Product', 'get_product_giveaway_data' )
		&& Wt_Smart_Coupon_Giveaway_Product_Public::is_a_free_item( $cart_item ) 
	) {
		$giveaway_common_module = Wt_Smart_Coupon_Giveaway_Product::get_instance();

		$coupon_code   = wc_format_coupon_code( $cart_item['free_gift_coupon'] );
		$item_id       = ( $cart_item['variation_id'] > 0 ) ? $cart_item['variation_id'] : $cart_item['product_id'];
		$product       = wc_get_product( $item_id );
		$product_price = Wt_Smart_Coupon_Giveaway_Product::get_product_price( $product );
		$giveaway_data = $giveaway_common_module->get_product_giveaway_data( $item_id, $coupon_code, $cart_item );
		
		$discount = Wt_Smart_Coupon_Giveaway_Product::get_available_discount_for_giveaway_product( $product, $giveaway_data );

		$sale_price_after_discount = $product_price - $discount;
		
		if ( $is_total ) {
			$sale_price_after_discount *= $cart_item['quantity'];
		}

		$out = '<span>' . wc_price( $sale_price_after_discount ) . '</span>';
	}
	
	return $out;
}