I am thinking of investing one. I found one a pretty good deal for a 100 bucks. overrites the memory (when full, it starts recording on top of the old record) I think it starts when the car starts and it shuts off 15 seconds after the car is turned off. Just to be safe is my reason.

What do you think? Should I go for it?

 

As long as you remove it from the car every time you park it somewhere, or you will find someone else will remove it for you.
If you leave the holder for it in sight someone will hope you have left it in the glove box, goodbye side glass and the camera if you did. you lose a $100 camera and $500 damage.
The same applies for GPS units.
There should be nothing left in sight in the car ever, even a useless item, as someone may misidentify it and think its something valuable and break in.

 

If you are looking for a cam, definitely look at Hero Cams

 

$100 for a dash cam, sounds like it would not be too terribly nice, and maybe on the larger side?? What is the resolution and how much time does it record? Is it upgradeable or sealed?

My setup cost much more than that, but I only put it in when doing certain things, as 180 said, things will desappear if not.