Our "flagstone bench installation" video will show you exactly how Hans puts one in for a customer.
It should take you about a day to install and cost about $250 in materials. Of course it depends on the type of stone that you use.
We use Colorado Red Flagstone on the job in this video. We had laid a flagstone porch and walkway for the client and he requested a bench to go along with it.
Here is a picture of it.
All you need to do is hit the play button and the video will start!
Here is Part One
Here is Part Two
Here is Part Three
As stated towards the end of the video, you also have the option of having a base from strip stones. It gives a different look to the bench that might be more appealing to you. It will cost a little bit more and take some more work.