1. Optional services: Ordering checks, for instance, costs money. Official checks, paper statements, the use of non-Higher One ATMs, these all result in small fees.
2. Penalties: Certain actions should never be taken by any accountholder, at any bank, anytime. Bouncing checks, overdrawing the account, etc. Basically, trying to spend money you don't have will result in a penalty. Most of these things are also not legal - writing a check knowing that it will bounce, for example, is considered fraud.
3. Inactivity fee: If you don't do anything with the account for 9 months, you will be charged the inactivity fee. This is designed to prevent the overhead from maintaining a 'dead' account - most of which will have balances under a dollar - from becoming overwhelming. If you want to avoid this fee, simply withdraw a little money at an ATM, or make a purchase, using your card every few months.