If I agree to a contract to purchase and back out I typically have a penalty.

This is most commonly ran into when you enter into contract on a property.

Your security deposit, in my state, for a rental incurs simple interest and is returned to you with that interest.

Why we let a company have us enter into a contract for what they can offer and then arbitrarily change the terms but not require you to agree to the new terms before charging you for the new terms … consumer protections in the USA are ass