It depends on traffic, what you looking to protect.
here is the startup model ( there is a smaller model also).
Thanks for replying Sir.
Actually we are planning to develop a national level data centre that will have all the data related to research on himalayan region . so It will be a huge one... Can u please suggest me some model of cisco for such huge data centre
If you have a budget - and kid of requirement you have suggested looking for Firepower 9300 ( if it is critical always deploy High Availability)
any further assistance required - contact me any time happy to help you.