If you are a registered business you are required to state this in any advertising as part of the Business Disclosure Act, therefore, it's important if you are a business to select the correct account 'type'.
Adverts for business sellers vary in price but some are still free depending on the area and category you are advertising in.
With a business account, you can also add your company logo, some information about your business and even your website address to give your adverts a real professional feel to them which buyers will trust.