For a limited time, and while supplies last, iTechDeals has the iTD Gear universal dashboard magnetic car mount holder for $4.79 shipped when you apply promo code ITD360 at checkout.
This is no doubt a small distributor, and I have no idea how much inventory it has. If it sells out, you can find countless similar products elsewhere, though typically priced closer to $10.This one uses a sticky-pad base to adhere to your dashboard, as opposed to some that clip into an air vent. You then stick a thin metal plate to the backside (or, preferably, inside) of your phone case. Now, when you get into your car, just plunk the phone onto the mount.