Fix-A-Flat
This could be the best $20 any car owner spends on a gadget, whether the car is a Mercedes or 1994 Toyota Corolla. Like the name says, this gizmo can fix a flat. It won’t work so well that a driver can keep going on a punctured tire for weeks, but it will enable the car to reach a garage for a more permanent fix without harming tire rims.
Fix-a-Flat stays in the trunk until an unlucky driver needs to use it. It almost magically will inflate on contact, sealing within seconds. For a car gadget that’s a little less practical but still very cool, see the following in-car wake-up call.