I used
{% if sale %}
<strike id="fullprice" style="display: block;">
{{ product|discount_price:""|currency }}
</strike>
{% endif %}
<span id="price">{{ product|discount_price:sale|currency }}</span>
This works without sale i.e., discount_price:sale|currency and throws an exception
Caught VariableDoesNotExist while rendering: Failed lookup for key [sale] in ...
Its important that both sale price and non sale price is displayed. How can I achieve this.