Best an older laptop
Basically, you can take as well as everything, since you need to program itself in the end only one editor. So there's something older.
That does not matter. Any office device can do that.
(Of course it depends on what you program or whether you want to test it on the same device)
How much is the device allowed to cost?
Almost any laptop that is suitable for programming would be suitable.
More modern versions of development environments like Eclipse already have some requirements for the system, but they are pretty modest. Here I would go after the recommendations of the preferred development tool.
Much more important is the user interface. The monitor pixels should not be too small, on the other hand as many as possible. That's the best time to take a look. The screen should be dull, while glossy screens look good, but have too many reflections to allow for fatigue-free work. I do not want to give up a number pad.
