Shopify development you can trust.

{%- liquid
  assign variant = product.selected_or_first_available_variant
  assign on_sale = false
  if variant.compare_at_price > variant.price
    assign on_sale = true
  endif
-%}

<div class="price">
  {{ variant.price | money }}
  {%- if on_sale -%}
    <s>{{ variant.compare_at_price | money }}</s>
  {%- endif -%}
</div>

{%- comment -%} Show a low stock note under 5 {%- endcomment -%}
{%- if variant.inventory_quantity < section.settings.low_stock -%}
  <p class="stock-note">
    Only {{ variant.inventory_quantity }} left
  </p>
{%- endif -%}

{%- form 'product', product -%}
  <input type="hidden" name="id" value="{{ variant.id }}">
  <button type="submit">Add to cart</button>
{%- endform -%}

{%- comment -%} Editable from the theme editor {%- endcomment -%}
{% schema %}
{ "name": "Product info",
  "settings": [
    { "type": "range", "id": "low_stock",
      "min": 1, "max": 10, "default": 5 }
  ] }
{% endschema %}