Shipping An Item To A Third World Country

I would say ask the buyer. Otherwise always Registered, Insured Mail for International Clients. That's how I ship.

Slightly off topic, but I don't think Mexico is a third world country.

I just put small orders in a standard #10 envelope, tape the coins (in 2x2's) to a sheet of paper and wrap it in two sheets of paper and send it registered. There's a form at the post office for registered mail, it's pricey though. You also need to have a CN 22.
Tip: Don't include an invoice in the shipment. If the item gets snagged in customs e-mail the buyer a copy of the invoice so they can deal with their customs agents. Saves you a lot of trouble on your end by ensuring that customs goes to the buyer for any duties not you.

In the states registered mail starts at $11.20 for the absolute cheapest according to the USPS site.

The thing you really need to check with the post office about is what actually translates across the boarder. What I mean is it doesn't really matter if you send registered vs priority if the registered mail service stops once its crosses the boarder. At some point theyre more than likely going to be handing your package off to the Mexican mail service, maybe Fedex or UPS if you send it so its more secure.

If its something valuable I would ask USPS, UPS, and Fedex how it will be shipped once in Mexico. You can use all the tracking and registration you want but if it all stops at the boarder it doesn't really do a lot of good

I rarely ship Internationally but when I do, I choose USPS Express mail only.

Sorry, didn't mean to sound like the Dos Equis guy.

When I was on ebay and sold coins outside the United States, I would send them USPS Global Priority w/Insurance.

I didn't see that option listed in your Poll Questionnaire .

I think the proper terms is emerging countries. I know some countries were once third-world but have benefited from having large populations and low wages.