add_filter( 'template_include', function( $template ) {

 if ( has_term( 'fabric-offers', 'product_cat' ) ) {

 add_action( 'woocommerce_before_calculate_totals', 'add_custom_price' );
    function add_custom_price( $cart_object ) {
         $custom_price = 50; // This will be your custome price
         foreach ( $cart_object->cart_contents as $key => $value ) {
            $value['data']->price = $custom_price;
         }

     }

    }
    return $template;

    });