A Miami mailbox: the guide to shopping in the U.S. and getting it to South America without surprises

Disclosure: Mercatren, the service used as an example in this guide, belongs to the same business group as losupe. We are saying so before you read any further. The advice in this piece applies to any package-forwarding service: these are the same mistakes people make with all of them.

The scene repeats every day. Someone in the United States finds the auto part, the phone, or the tool their family needs in Venezuela, Colombia, or Chile. Into the cart it goes. And at checkout comes the same wall: "we don't ship to that country."

The way around it has an old, unglamorous name: the mailbox, or package forwarder. It is a physical address in the United States — usually in Miami — that a company assigns to you with your own number. You shop at Amazon, at Walmart, anywhere; you enter that address at checkout; the package arrives there. Then that company ships it on to your country.

What's new: Mercatren opened its own

Until now Mercatren worked one way only: you bought from its catalog and a store in your country handed you the goods. As of this month it also has its own mailbox in Miami, with one important difference: you no longer have to buy from Mercatren. You shop wherever you want — Amazon, eBay, Walmart, SHEIN, Temu, Best Buy, Target, Home Depot — and use the mailbox only for the transport.

The Miami warehouse is operated by BESTWAY GROUP INTL. CORP., which receives packages on Mercatren's behalf. The flow, per the service's own page, is four steps: you create the mailbox (free, one minute), shop anywhere, they receive your package and notify you with a photo, weight, and dimensions, and then they ship it to you.

In parallel, the company split its storefronts by country. Four separate sites now run, each with its own merchants and payment methods: mercatren.com (United States), mercatren.com.ve (Venezuela), mercatren.com.co (Colombia), and mercatren.cl (Chile). Anyone whose store or orders lived on the original site and was based in Venezuela will now find them on the Venezuelan domain, same login.

The five mistakes that get a package lost

This is what actually matters, and it applies to any forwarder on the market, not just this one.

1. Your mailbox number isn't a detail — it's your name

A Miami warehouse takes in hundreds of packages a day and every one of them is addressed to the same street. The only thing identifying a box as yours is your number. Forget it and your box arrives, gets unloaded, and belongs to nobody.

It goes right next to your name in the name field — like this: Your Name MT-1234 — and again on address line 2. Why twice? Because some stores strip line 2 when they process the order. Putting it in both places is the insurance policy.

2. Consolidate before you ship

Sending three boxes separately costs considerably more than sending one box with all three things inside. Nearly every forwarder lets you hold and consolidate. If you're buying several items, buy them in the same week and ship them together. This is the single biggest money-saver on this list.

3. The weight you're charged isn't always the weight on the scale

This one catches beginners every time. Air freight bills by volumetric weight: a huge, light box takes up the space of a heavy one and gets charged like it. A pillow weighs almost nothing and ships like it weighs a lot.

Before buying anything big and light, check the box dimensions, not just the weight. And where possible, ask them to remove the original packaging and ship the product in something smaller — most forwarders will.

4. Some things simply don't fly

Even when a store sells it to you without blinking, some goods can't go on a plane or won't clear customs. The usual suspects: loose lithium batteries (ones inside a device are usually fine; loose ones are not), aerosols, perfumes, and flammable liquids, paint, and anything weapons-related, right down to accessories.

Every forwarder publishes its list. Read it before you buy, not after: if the goods reach the warehouse and can't leave, you've already paid for the product and the domestic shipping for nothing.

5. Keep the invoice — and declare the real value

Customs in your country will ask what it cost. Save the store's confirmation email from day one.

And here's a warning worth taking seriously: don't ask anyone to declare a lower value than you paid. It sounds like a clever way to pay less duty and it goes wrong in two directions — if customs catches it, there's a fine and a hold, and if the package is lost, insurance pays out the declared value, not what you spent.

One more piece of advice almost nobody gives

Think about returns before you buy. While the package is still in Miami, returning it to the store is easy and often free. Once it has left for your country, returning anything is prohibitively expensive, and in practice nobody does it.

So if you're buying clothes or shoes — the most-returned items there are — check the size while the package is still at the warehouse. Several forwarders send you photos of the contents for exactly this reason. That's the moment to say "this isn't it," not after it has crossed a continent.

Mailbox or local store: which one you want

These are two different routes and they're worth keeping straight:

• The mailbox is for what you can only get in the United States: a specific part, a model that never launched there, a brand that isn't sold locally. You pay for the product plus the freight, and you wait however long it takes.
• The local store — buying on your country's site so a merchant there hands it over — is for what's already in your city: construction materials, an appliance, a battery. You pay from the United States and your family picks it up without waiting on any airplane.

For a box of screws, a mailbox makes no sense. For the part nobody has, it's the only way.

How to start

Creating the mailbox is free and takes a minute at mercatren.com/es/casillero. The full address appears inside your account, not on the public page — and that, small as it seems, is the right call: a warehouse address published without a code is an open invitation for packages belonging to nobody.

And the final piece of advice, the dullest and the one that prevents the most grief: make your first order a small one. Something cheap, to see how long it really takes, how they notify you, and what they charge. Then send the thing that matters.