If you want to get a custom text on your BUY-button, you may add the following script to your page:
<script type="text/javascript">
(function() {
var nodes = document.querySelectorAll(".ddr-widget__shopify-product .ddr-shopify-product__button a div"),
text = 'YOUROWNTEXT';
for (var i = 0; i < nodes.length; i++) {
nodes[i].innerHTML = text;
}
})();
</script>
Change the text = 'YOUROWNTEXT'; string to what is needed and that's it. You'll have whatever you want on your BUY-button.