Collision coverage is limited to the actual cash value of the vehicle, and requires a deductible, which is the amount you'll need to pay before receiving benefits. Higher deductibles lower your premium but increase the amount you must pay out of your own pocket if a loss occurs. Ask yourself how much you would be willing to pay on short notice in order to save on your premium, or talk to your agent.
Collision coverage has a deductible, which is the amount you pay before your coverage helps pay for your claim. You can typically choose the amount of your deductible when you buy coverage. So, if you choose a $1,000 deductible and your car is later damaged in a covered accident, you'd have to pay $1,000 toward repair costs. Your collision coverage would help pay the rest, up to your coverage limit.