To rename 0.00$ to Free in Squarespace, you can use this code to Code Injection > Footer
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.0/jquery.min.js"></script>
<script>
$(document).ready(function(){
$('.product-price:contains("0.00$")').addClass('free-product');
});
</script>
<style>
.product-price.free-product {
font-size: 0 !important;
}
.product-price.free-product:before {
content: "Free";
font-size: 18px !important;
}
</style>
Result
