What Were Some of Your Unexpected Costs When Starting Your Business?

General question that I would like to know the answer to. Starting a business can obviously be pretty costly and there are plenty of obvious costs that come with it, but what are some of the things that sprang up while you were starting out that you didn't expect? I need to know for an entrepreneurship class, so anything would be greatly appreciated. Feel free to say things specific to your business, whatever it might be.