For a small business selling online in Latin America, the “where do I advertise” debate usually ends in two options: ads inside Mercado Libre, or Google Shopping sending traffic to your own store. They are usually compared by ROAS, which is the wrong comparison. The real question is who owns the customer after the sale, and how much margin is left.

How each works

Mercado Libre Ads (product ads inside Mercado Libre) promote your listings in marketplace search results and product pages, paid per click, where shoppers are already comparing. They convert fast.

Google Shopping shows your products with image and price on Google and sends the click to your own store. It needs a catalog in Google Merchant Center and a Google Ads campaign.

What actually differs

Who owns the customer. On Mercado Libre, the customer belongs to the marketplace; next time they search there and see competitors beside you, and every repeat sale is paid for again. In your store, you have their email and they can come back directly. If your product is repurchased, that matters a lot; see LTV and CAC together.

Margin, not ROAS. Marketplace ROAS often looks better, but the sale commission (varying by category and listing type) and often shipping come on top. Compare margin per sale after all costs, minus ad cost per sale. Details in how to calculate ROAS.

Speed of learning. Mercado Libre Ads answers in days. Google Shopping needs more time and work up front, mostly on the feed.

The work behind it. Google Shopping lives or dies by the feed; see Google Shopping in-house or agency. On Mercado Libre, the listing itself (title, photos, price, seller reputation, shipping) matters as much as the ad.

How to decide

  • You sell almost entirely on Mercado Libre, no own store: start with Mercado Libre Ads on your best-margin listings.
  • Own store and repurchased products: prioritize Google Shopping. Customers won in your store are assets; customers won on the marketplace are rented.
  • Both: Mercado Libre Ads for volume and product testing, Google Shopping to build your own customer base. Judge each by margin.
  • High-ticket, one-time purchase: the marketplace weighs more, because trust in Mercado Libre converts people who do not know your brand.

What gets forgotten with Google Shopping

  • Split campaigns by margin, not just category.
  • Performance Max vs standard Shopping: PMax can work, but with little data it blends brand and new traffic. See Performance Max: when it works.
  • Payment methods: an own store without installments or Mercado Pago competes at a disadvantage against the marketplace. More in entering LatAm.

If you invest in both and cannot tell which leaves more margin, an audit starts with exactly that calculation.