add_action( 'edd_format_amount_decimals', 'kjm_format_decimals' );

function kjm_format_decimals() {
	return 0;
}

add_filter( 'edd_purchase_link_args', 'kjm_adjust_purchase_link_text' );

function kjm_adjust_purchase_link_text( $args ) {
	$download = new EDD_Download( $args['download_id'] );
	$option = edd_get_option( 'add_to_cart_text' );
	$price = edd_currency_filter( edd_format_amount( $download->price ) );

	if ( ! $download->is_free( $args['price_id'] ) && ! $download->has_variable_prices() ) {
		$args['text'] = $option . ' for ' . $price;
	}
	return $args;
}