Hi, the answers may or may not vary depending on the state in which you live.
This info is from my experiences.
In Florida, Gap insurance is automatically included in the lease price. No extra cost. Zero.
But if you FINANCE, not lease, you may want to add Gap insurance to your auto insurance policy. For me this was less than $25 per YEAR, with Progressive.
Car dealers sometimes try to trick people into paying $100s of dollars per year to buy it from them when they finance (not lease) a car through the dealership.
Hope this helps.