You never have to exercise if you don't want to so there's a fixed maximum cost
Correct me if I'm wrong, but I assume there is a good reason why banks require additional paperwork from people who want to trade options/futures that must be renewed on a regular base.
Both call and put options are optional for the option holder to exercise (realistically you only ever exercise if they are in the money, or worth something). You usually don't need any additional paperwork to buy options
Writing options on the other hand has unlimited potential downside. It's much harder to get brokers to allow you to do this. Many will only let you write "covered" options - meaning you also hold the underlying shares, which limits your downside