How to Use Bundles, Packs and Cross-Selling in eCommerce

There are 3 ways to make more money in an online store: attract more visitors, improve conversion, or get each customer to spend more per order. The first two require investment, but the third, when well executed, practically pays for itself.

The order value, or average order value, is one of the indicators that can be neglected in eCommerce, especially in small or medium-sized businesses.

A lot of effort to attract traffic, a lot of investment in advertising, and then... the customer buys the product they had in mind and leaves. That's all.

But this is where bundles, packs and cross-selling have their strongest argument: you can sell more to someone who has already decided to buy, without spending one more euro on customer acquisition.

According to McKinsey data, stores that implement bundling strategies increase their sales by 20% and their profits by 30%. And Amazon attributes up to 35% of its revenue to cross-selling and upselling. These are figures from a giant, but the mechanism works the same in catalogs of 100 products as it does in catalogs of one million.

Before explaining how to apply them, it is worth clarifying exactly what we are talking about, because these three terms are often used interchangeably... but they are not the same.

A bundle groups several products into a single offer with a combined price.

For example, a coffee machine, a grinder and two packs of coffee can be sold together as a bundle. The customer buys the whole set at once and usually gets a better price than buying each product separately.

The included products can continue to be sold individually while keeping their own SKU and stock.

By contrast, when several items form a single closed product with its own SKU, we can speak of a kit, a closed pack or a composite product. For example, a cosmetics case prepared by the manufacturer containing a cream, a serum and an eye contour treatment.

In practice, the terms bundle, pack and kit are often used as synonyms. What matters is not so much the name as how the set is sold and managed:

Therefore, there is no single universal difference between a bundle and a pack. Each store or platform may use these terms differently.

Then, there is cross-selling, which works differently. Here, products are not grouped together and no package is created: complementary products are simply recommended at the right moment.

You have certainly seen this strategy hundreds of times. The classic "You may also be interested in" on a product page, the "Complete the look" section in fashion stores, or Amazon's "Customers who bought this product also bought..." are very clear examples of cross-selling.

You may also have heard about upselling, since both concepts often appear together. The difference is simple: while cross-selling encourages the customer to add complementary products to the cart, upselling encourages them to choose a higher-end, more complete or more expensive version of the product they are already considering.

Although both strategies can increase the average order value, upselling is not about selling more items, so it does not quite fit within the scope of this post.

The golden rule is that they only work well when the products included have greater value together than separately. When that perceived value justifies the combined price, the user clearly understands that they are getting a better deal.

Be careful with this: if the customer can buy the same products individually for less money (or for the same price), the bundle has no reason to be.

Let's look at three situations where using bundles or packs makes perfect sense:

Cross-selling is probably the easiest technique to implement and also the easiest to implement poorly. There is a very thin line between cross-selling that converts and cross-selling that irritates. Wondering what the key is? Relevance.

Telling someone who has just added a book to their cart that they can also buy a television is not cross-selling; it is simply indiscriminate noise. But suggesting a bookmark, another book by the same author or a travel reading light makes perfect sense. The criterion is simple common sense: the suggested product must be useful in the context of what the customer is already buying.

Besides context, timing is just as important as the product itself. There are three moments where cross-selling works best:

More options do not necessarily mean more sales. When the customer sees 15 suggested products on the product page and another 12 in the cart, the most common reaction is simply to ignore them all.

The rule generally followed by stores with the best cross-selling performance is a maximum of three suggestions per touchpoint. Just three, but carefully chosen, with a clear image and a visible price. You will find they perform better than an endless carousel of automatically generated "related products" with no real criteria.

The three metrics to monitor are AOV (Average Order Value), the conversion rate of the cross-selling modules, and the percentage of orders containing more than one product.

If AOV increases but the overall conversion rate falls, something in the implementation is creating friction.

If the cross-selling modules receive many impressions but very few clicks, the problem is the relevance of the suggested products.

If all those metrics are performing well but profit margins do not improve, check that the products included in bundles or suggested through cross-selling have sufficient margin to make the strategy profitable rather than simply impressive on paper.

Most eCommerce platforms include some type of native functionality for related products or packs, although the level of control varies considerably. Before installing anything, check what your platform already offers. Very often, the basic module is enough to get started without adding unnecessary complexity.

For more sophisticated bundle management, there are tools that analyse your store's real order history and generate suggestions based on the products customers naturally purchase together, instead of requiring you to configure everything manually, product by product. That is the difference between guessing what works well together and knowing it through data.

For email marketing with personalised product recommendations—where post-purchase cross-selling performs best. Klaviyo includes this functionality and integrates with most email marketing tools on the market. In any case, the platform matters less than the criteria used to configure it.

A basic module with well-designed recommendations performs better than a sophisticated one full of irrelevant products. And the only way to know which combinations convert in your specific catalogue is through testing: what works in an electronics store will not necessarily work in a grocery store, even though the underlying principles are the same.