It depends on the type of business you plan to start.
If you just want to start an online store from your home then you don't need a business license to do so.
However if you plan to start a business that works out of an office space and you hire employees then you do need a business license to operate.
Having a business license especially if you're selling or providing services to customers in that business can really help boost sales and revenue since more customers and people will be willing to do business with a properly licensed business because the license helps to set your business apart from those fly by night businesses.
Having a business license is not that expensive or hard to get and shows you're serious about your business.