For incorporating a company, you should have minimum 2 subscribers for a private company and 7 subscribers for a public company . 2 directors in case it is a private limited company and three directors in case of a public limited company who can be amongst the subscribers themselves. Also, the minimum share capital would be 1,00,000 in case of a Pvt held company and 5,00,000 incase it is a Public company. As far as the expenses are concerned the rates vary from professional to professional. I suggest you opt for a partnership firm, once you establish yourself well then you can opt for a company.
Please do write in case of further queries