I'm trying to research the economy of running a direct mail campaign
in a foreign (non-US) market.

A postcard, for example can be sent from the US to the UK for $0.70.

On the other hand, a postcard sent domestically in the UK via 2nd
class mail would be 21p (~$0.38).

If I were to send 1000 postcards out, from the US to the UK it would
cost about $700.

If I were to send 1000 postcards out, from inside the UK to the UK, it
would cost about $380.

It would seem so much cheaper to send a package from the US to a
friend in the UK filled with pre-addressed postcards and 2nd class
stamps.  Once the package arrives at one address the person would open
the box, take all the postcards and drop them off into the UK mail
system.

However, to do this, one would need a friend in the UK, or whatever
country you were targeting in the mailing campaign.

I'm wondering if there are commercial services that offer this type of service.

I'm looking for into doing a direct mail campaign for the UK, France,
Germany, Spain, Canada, Mexico, China and Japan.

Thank you for your question.
 
I believe that to answer it well, your question will require more time
and effort than the average amount of time and effort associated with
this price. Here is a link to guidelines about pricing your question,
in the pricing guide: https://answers.google.com/answers/pricing.html

You can try at http://www.correos.es/contenido/12E-PublicidadMD/01-Publicorreo/12E01-Publicorreo.asp

"correos" is the national post service in Spain. Here you can send,
for example, with at least 500 destiny adress, with the same card and
differents addressees, from 0,145 ?.

For other countries, from 0,38 ? /postcard.

And just for spain, if you choose not to put the adress where you send
it (it means, they put the cards on the mailboxes of the choosen
zone), from 	0,08 ?.
http://www.correos.es/contenido/12E-PublicidadMD/02-Publibuzon/01-MDPublibuzon/12E0201b-PublibuzonTarifas.asp