I would say go with what bagman mentions, but if you want to go quality at it's lowest cost, then maybe you could get the incan G2, which goes for $36. Also, that G2 must be OK, because a lot of soldiers are using that one model now in the field. But if you can go with an LED or G2L ($65) model, I would do that just because of the hours and strength of the LED SureFire G2L. In your line of work, IMO I would consider getting the SureFire 6P Defender ($74) at a minimum, which has the crenellated strike bezel, in case you want the added benefit of using your light to tear a chunk out of a convicts face while he is blinded. Better yet, the LED model of that one is the 6PDL for $100.
Good luck and stay safe.