Websites Design

We are a group of companies and in need of a comprehensive website from corporate website linking to to subsidiary companies website which have products and/or services. No significant database needed as products are very few and focused in different industries. There are about seven companies which require different websites. Please I am looking for best and most cost effective way of achieving this project. I have 2 months maximum timeline. I am not sure how much this will cost and so need for proper scoping of the project.