Over the last several years, email became the most common way to contact buyers. It is quick, efficient, and cost-effective. But is it the best way, now, to contact buyers? What about using mailers instead?
Using snail mail can offer a new experience for both buyers and producers. Among the hundreds of emails a buyer receives daily, your email can easily be lost. 
Whereas, a letter, package or postcard can stand out from other marketing messages.
Aeolidia – The Shopify Experts shared the following suggestions:
… “Snail mail” packages can be great because they’re so personal — but they can also be time-consuming and costly. Some of the things that I think are most important are:
1) Since stores get a lot of mail, if you’re going to mail something, make it stand out.
2) Consider it an experimentation process. So, decide to try something for this month, see how it works, and then try something that builds on your findings for next month. Perhaps this month you send a paper note instead of a followup email, but still do that first introduction via email. But different things work for different makers, so we really suggest trying different tactics.
3) Remember that you can do different things for different stores. So if there are, say, 5 this month that you think are just “no brainers” for you, maybe you send your physical mailer to those.
Wholesale in a Box adds to the discussion by suggesting the following:
One advantage of sending packages is that you have a richer medium to express your style, enthusiasm, and brand. The disadvantage is the cost in money, time, materials, and postage AND not every retailer wants you to send them an onslaught of stuff. … a package can so deeply forge a connection that it can certainly be worth it!
If you are thinking about using mailers, letters or packages to contact buyers, I would recommend that, unless you know the buyers well, you contact them via email first. Every buyer is different and has different likes and requirements for buying. And since mailers can be costly, you don’t want to send them out unless you are sure the buyer is interested or expecting your package.
Postcards, on the other hand, are great tools for announcing a new product, inviting a buyer to your booth at a show, or just for saying thank you for your order. And the cost-effectiveness of postcards makes them easier to produce and mail.
I enjoyed the final comments from the Wholesale in a Box article:
We believe in starting, even though you will likely mess up along the way. Getting your work into the world is worth the occasional embarrassing email you send and even worth the 15 rejections you get for every one account you gain. Even when you think you made a fool out of yourself, it’s more likely you made a human out of yourself.