What is the best effective marketing strategy to be use, and could make the business grow yet simple and affordable to the business?

The kind of marketing tool to use, greatly depends on the kind of business and the target customers. However, in general, in this digital age SEO, Social Media Marketing and Google Adwords & PPC can be pretty useful to build a brand image and are not too expensive as well.

Social media is very affordable and simple. but again it depends on the budget your business is going to invest that really matters.