Oriental Trading Company has some small metal mailboxes for only a few dollars and you can even decorate them. I like this mailbox so it is the one I am ordering for us to use. Here is a picture.
I have published the postcard prompts I have made so far on Scribd. There are 12 countries so far but I will be making more in the next few days also.
Postcard Writing Prompts
These print best if you print them on cardstock and print the fronts first and then flip the paper and print the backs. I hope you enjoy them and please feel free to comment and let me know any ideas you might have for other countries.