It would also help to know what duties the officer in question will be undertaking.
If he's working the nightshift in a bad neighborhood, the officer might want a light with a little more heft such as a 3D Mag-Lite with an upgraded LED.
If duties include mainly citations, vehicle-centric work then a light with both High and Low modes would be useful.
If working in the city, a light with a wide beam that shines 20m may be useful.
If working semi-rural or bush, a light with a tighter beam that shines 100m may be useful.
If plainclothes, perhaps a smaller concealable light.
If participating on a specialist weapons unit, a dedicated combat light designed for use with a firearm may be useful.
A basic description of frequent duties, and budget, would help us suggest. Just understand that a budget of $50 won't go very far in the world of high quality illumination tools. People who do not know of the latest advances in flashlight technology might think $50 as an upper limit and anything beyond as ludicrous.
If I was a LEO I would set a budget of $250, which includes light/holster/batteries ... If I didn't have $250 to budget for it, I'd make do with whatever I had at the moment and save until I did.
edit:
I cant send you a private message. I have a SureFire 6PX Pro, very lightly used, that I am looking to sell. I live in QLD. To get this light in Aus is $138 + shipping ... I can get it to you for $75 + shipping. Indicate if you're interested.
sorry mods but he cant PM yet.