It is online gateway that guides small and medium type of businesses. The turnover should be minimum 21 lakhs so that you can submit gst return. A lot of businesses and individual donot file return as they think it is a difficult work and require a lot of knowledge. Here comes gst suvidha kendra who is low fees does your return and also teach you same. The setup cost for a kendra is around 25000 and monthly income is 30,000.