AccuTracking

If I purchase the starter kit for myself, and turn it on and I happen to forget my phone in the back of my husband's trunk, will I be able to track the phone without him knowing?

Also, when the phone is on, am I being charged air minutes? Are there refunds?

Yes it'll track in the most cars' trunk but the GPS reception depends on the make and model of the cars. You should test with your car.

To keep it hidden, the phone ring should be muted.

You are charged $0.20/day for the unlimited Nextel data plan, which is required by AccuTracking. There'll be no refunds once the phone is activated under your name.

Why would the phone ring?
Is there a limited time in which I have to keep the service or can I cancel the service at any time?

The phone rings when someone dials a "wrong number".

You recharge your account month by month so whenever you used up the account credit it's over. You can come back later and recharge: http://www.accutracking.com/pricing.html