<div class="price">
  &yen;5,000
</div>
→
<span>
  &yen;3,000
</span>
.price {
  position: relative;
  display: inline-block;
}

.price::after {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 100%;
  height: 2px;
  background: red;
  transform: rotate(-10deg);
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.