Berlin must be the best place to get postcards in the entire world. If you like sending postcards, you should definitely make a journey to Berlin with a weighty bag of Euro coins (and one of those sponge damper thingamabobs – because you wouldn’t want to actually use your tongue to dampen 60 postage stamps like one silly me did many years ago when sending postcards to her entire high-school class).
The best place to get them (in my humble opinion) would be at Unter den Linden – the street that runs towards the Brandenburger Tor and is lined with a choice of trendy souvenir-slash-bookshops flanked by postcard carousels.
You should then get a bag of Gummi Bears (which you should pronounce exclusively as [goomy beahz], like in Hedwig and the Angry Inch) and try to eat one at a time like you’re supposed to (you’re in Germany, after all) whilst scribbling silly notes to your mates on a bench in the park. Perhaps you might even glance upwards and – to your sheer delight – spot ninety-nine red balloons floating in the summer sky. But even if you don’t, there’s always something to write home about from Berlin!