Are verbal agreements legally binding?

Yes verbal agreements, in the eyes of the law, are contracts, which are just as valid as those which are written. The vast majority of contracts you make are not written, but are verbal or are implied by your conduct. Actions like taking a ticket from a ticket machine, or paying on a bus, or routinely allowing someone to clean your windows, or hiring a taxi, or buying a newspaper, are many examples of contracts we make all the time without writing them down.

But is this contract verbal or written? You say you "signed up". If you signed something, it is written. What were the terms? What were the terms you thought you were agreeing to?

One thing you mention is a "free trial". Generally, if something is "free", then it is not a contract, unless something, not necessarily even money, is given in return. Also if someone tries to push something onto you which was not requested by you, it is not a contract. It would be grossly unfair to send you, without any request from you, a magazine on a regular basis, and then tell you that you must pay for it. It would be equally unfair to require to keep something you did not ask for, or to compel you to return it.

You do have copies of the "free trial agreement" and gave them proper notice as to your intent not to continue the service?

This is what they count on, you forget or don't read the contract.

Verbal agreements become mot when a written one is ratified by you through your actions or lack there of.