Everything depends on the Complexity of your project and what you want to offer. Your site can be related Bitcoin Faucet, Bitcoin News and information site, Bitcoin Trading site or Exchange , Bitcoin related Blog and forum, Bitcoin Mining Projects, and  Bitcoin Gambling Projects. For small site it can cost you around $200-maximum $500 but for bigger projects like Exchange, ICO ,Mining it can cost you $3000 or even more than that, because here it requires more resources, Manpower and high-tech tools for completion of your projects.