Shopify App: Product Samples
Button that will show on the front end
The item being added to sample list to checkout
Settings – applying the sample to specific category of products
Product Template – Attaching the buy a sample to buy buttons block
Code for buy a sample
<div class="product-form__buttons p-relative buy-sample" product-samples-button="">
<div class="sample-price">$10.00</div>
<button type="button" class="product-form__submit button button--full-width button--primary" title="Buy a sample and go to cart to purchase more than 1 sample quanity of this product." product-samples-button="">Buy a Sample</button>
</div>