Hey Amish,
We reviewed the idea and wanted to share an update with you. 
- There are similar platforms out there like https://moneybhai.moneycontrol.com/, you should definitely check this out and verify if there is anything you can improve in the current products. If not please do assess if it is worth spending time and effort in building this product.
- For this platform, you will need to spend on obtaining market data. Please check if purchasing data from data vendors is feasible as there are services like the one we linked above available for free.
- If you want help with market data during the development of the app, you can explore an opportunity to apply for the SEBI sandbox. However, you will still need to pay for the data once your Sandbox term ends. You can read the revised regulations below -
- You should also read about Stock trading gaming and if in-app purchases are allowed. Please refer to this article by Rainmatter -
Stock trading games & copy trading platforms in India? – Z-Connect by Zerodha Z-Connect by Zerodha
Please do let us know if you have any questions. You can always reach out to us at [email protected].