add_action( 'wp_footer', 'my_footer_js' );
function my_footer_js() {
	if(is_product()){
	$product = wc_get_product( $post_id );
	;
?>
<script src="https://angus.finance-calculator.co.uk/js/imegaonestep.js"></script>
 <script>
 imegaCheckout.init({
 priceElement:'.yourPriceElement',
 apiKey:'ab49988ae4995727941d4b4c76127c86',
 insertion:'after',
 element:'#ds_div',
 anchorTemplate:'simple',
 vKey:'< YOUR VERIFICATION KEY >', //optional
 margin:'20px 0', //optional
 width:'360px', //optional,
 amount:'<?php echo $product->get_price(); ?>', //optional,
 image:'/images/products/product123.png' //optional
 });
 </script>
<?php
}
}