You can do that with teslas. Buy two keys (they at those credit cards sized keys) and you pair them on your own. Two for $40. Do it right at home. You can pair multiple cars to a single key. Or make guest keys

▲

XorNot 3 hours ago | parent [-]

This works for most modern Toyotas - there's a sequence of door openings which put the car in pairing mode and will link a new key.

	▲	ronnier 2 hours ago \| parent [-]
		But you have to buy an expensive key. I have two Teslas and a Toyota and my Toyota is so annoying that I even have to have a key. My Tesla just uses my phone (the credit card keys are totally optional)