{% assign total_saving = 0 %}
{% for item in cart.items %}
{% if item.variant.compare_at_price > item.variant.price %}
{% assign saving = item.variant.compare_at_price | minus: item.variant.price | times: item.quantity %}
{% assign total_saving = saving | plus: total_saving %}
{% endif %}
{% endfor %}
You Saved: {{ total_saving }}