The actual paperwork to create your company should not cost too much. You can probably do the paperwork yourself if you do not want to pay for a lawyer. But check with a lawyer first just to find out the fees and his fee. It may be worth talking to him and not making mistakes. After that it should not cost you anything to sign deals with distributors. They want the business too. But dont expect to get all the big brands if there is another shop right up the street. For accessories like metra, it should not be a problem.