http://ecx.images-amazon.com/images/I/61PNDeIsvQL._SX522_.jpg
Or you can go really expensive with this one: https://s-media-cache-ak0.pinimg.com/736x/9c/48/a3/9c48a3d3c5792f034b97af00a6900ffc.jpg
But I didn't feel like chucking out money not only for the garden but also shipping and possible custom fees if sent from America, for something that is basically a frame filled with sand and three stones. And then it occured to me: I can do that. I already have the sand and the stones and even a small rake, just fresh this Christmas - all I need is a deep picture frame which is more like a shadow box.
So I went and bought a cheap picture frame in the pound/dollar shop. Costs: 1,50 Euro.

As it was blue and not black like I wanted, I painted it quickly with a sharpie / Edding.

I was even lazy and didn't do the backsides that don't show on the pic ;)

And voilá!

My other customizations