This is the advise I will give you, take it or not thats up to you.
Cheap radars do not work. By the time the cheap radar starts ringing, you are practically next to the cop that clocked you. Keep in mind cops can clock you from miles away IF they want too.... so basically you need a radar that will detect the k and ka bands that the cops emit from a far distance. 2 of the most reputable brands that work are valentine one or escort 8500's... there are more expensive ones.... but they go into the thousands...
so the moral of the story is... radars are something you can't go cheap on... if your going to go cheap... then dont get an radar... because your wasting your money.
Update: I forgot to add in, when cops use their laser (device that is capable of clocking you miles away) alot (even expensive ones) will only detect it when the laser is triggered.... so it makes it harder for you to detect if the cop is clocking speeds.... something to think about....
Story
Not so long ago I was late to work so I was going a little over speed limit (luckily) and all the sudden my escort 8500 went berserk.. it displayed laser beam on the led screen... the cop that was clocking was like maybe 50 ft away... I lucked out on that one... but Im sure he would of pulled me over if I was going a little bit faster because he was giving me a dirty look.
heheheheh sorry had a typo