Shop establishment license should cost around Rs. 3,000 - 4,000 keeping one employee in mind. The cost increases depending upon the employees. For around 50 employees, the cost should be around Rs. 12,000 - Rs. 13,000
For sole proprietorship firm, you don't need registration like any partnership or pvt. ltd. companies. Just make sure you have PAN card, shop establishment license and address proof (mostly MTNL or electricity bill) ready for bank account opening.
Once that is done, you can apply for service tax number too (if required)
I don't think you need anything else to get started.