They vary, Depending on what you want out of your V1.
I bought mine from an LTr on this site. I paid 275.00, and I orderd the concealed display, case, and audio adapter from V1 directly. So, all in all, I am still under the cost of just the unit from V1.
Keep in mind when you buy a used one, you need the serial number. Go to www.valentine1.com
and then click "upgrades" and then input the serial number to see what if any upgrades were available. Do this BEFORE YOU BUY IT!! Then it will give you a list of all available updates etc. available to you, and then you can call them for a cost for the upgrade. The one I bought, the only thing it is lacking is the POP feature, which, being in law enforcement, I know is not used here in Colorado yet. (maybe a couple agencies, with new grants bought them, but not statewide) I know CSP isn't using them, and the ONLY agency I am aware that is using it as a direct replacement and is using it agency wide is California's LA County.
I am not much of a speeder, but do know I lose track like others, and I ONLY do this on a bike, in a vehicle I am the slow guy that is upsetting you.
If you have an officer sitting in hiding, and he has Instant On(which I do) I do not care how much money you spend, or what detector or EVEN JAMMER you have, if you were the officer's target, in less than .5seconds.."Tag! Your It"
I pulled over a lotus last weekend....you know the little one that is on a Celica frame...well anyway..he had a NEW V1, and I hit him with instant on, 64 in 35 and I locked him and when I approached the car, he was pretty upset and didn't believe it that I had clocked him because his radar detector didn't go off. He said "This is the best on the market, and if it didn't go off, you didn't get me" I then chuckled as I asked him to exit his vehicle and sit in my front passenger seat as I wrote his citation, and while he was there, I hit 2 more cars to show him the feature, he still wasn't convinced, so I rewound the incar cam(with radar/speed interface) and let him watch himself come in, his speed shown on radar on the screen, then shows me "lock" it and then me pull him over.
So, keep in mind....if you are the target....chances are, it is to late. So, when you are out in front on your own and not a care in the world.....make sure your Driver's license is handy, you will need it.
I am not a traffic cop, I primarily deal with narcotics, but when on duty and you see someone almost 30+ over in a residential area....you kinda become a traffic cop.