There used to be specific pages that you can embed within your site, like just my men category, I want to embed just a list specific product categories on different pages of my site, and specific products. (ex.http://quoteonclothing.spreadshirt.com/men-D1, this is what I used to use)
Hiya - I’m not entirely sure what you mean? Could you please elaborate?
At the same time, I’m no developer so that could also be why 
If you use the embedded (javascript) version, you may have already something like:
<div id="myshop"></div>
<script>
var spread_shop_config= {
"shopName" : "SHOP-ID",
"locale" : "en_US",
"prefix" : "//shop.spreadshirt.com/",
"baseId" : "myshop"
};
</script>
<script type="text/javascript" src="//shop.spreadshirt.com/shopfiles/shopclient/shopclient.nocache.js"></script>
Then just add this:
<script>
window.location.hash = "!-LI**designID**";
</script>
Whereas LI**designID** could be one of the other deeplink parts noted here:
Sadly, I can only find the german language explanation.
https://developer.spreadshirt.net/display/spreadShop/Deeplinks+und+URL's