您可以针对它们的包装器类.variations.variation-price-wrap{display:flex；}

null

.variations.variation-price-wrap{display:flex;  
                                 justify-content:space-between;}
p.price {
    display: flex;
    flex-direction: column;
    margin: 0;
}

<div class="woo-button-area">

            <div class="variations variation-price-wrap">
                <div class="variation-options">
                    <select id="opt" class="" name="attribute_pa_opt" data-attribute_name="attribute_pa_opt"
                            data-show_option_none="no">
                        <option value="opt1" class="attached enabled">Option 1</option>
                        <option value="op2" class="attached enabled">Option 2</option>
                    </select></div>
                <div class="woo-price-area">
                    <p class="price">
                        <del><span class="woocommerce-Price-amount amount"><span
                                        class="woocommerce-Price-currencySymbol">£</span>9.00</span></del>
                        <ins><span class="woocommerce-Price-amount amount"><span
                                        class="woocommerce-Price-currencySymbol">£</span>5.00</span></ins>
                    </p>
                    <div class="wc-availability"></div>
                </div>
            </div>


            <div class="single_variation_wrap">
                <div class="woocommerce-variation single_variation" style="">
                    <div class="font80">
                        <a rel="nofollow" href="#details" class="csspopuptrigger" data-popup="details">Details</a>
                    </div>
                    <div class="prosconswidget">
                        <div class="wpsm_pros mt20 font80">
                            <ul>
                                <li>Test li</li>
                            </ul>

                        </div>
                    </div>
                </div> </div>
            </div>