Shared web hosting service refers to a web hosting service where many websites reside on one web server connected to the Internet. This is generally the most economical option for hosting, as the overall cost of server maintenance is amortized over many customers.
Cost: $3 to $5 / month
Strengths: Low cost; very cost effective;
Typical scenarios: Shared hosting is great for hosting a personal blog or personal website with relatively low traffic (e.g. a few thousand visits / month) and no critical business. Shared hosting is also often used for testing different web projects by developers.
A managed hosting service is a type of Internet hosting in which the client leases an entire server not shared with anyone else. This is more flexible than shared hosting, as organizations have full control over the server(s), including choice of operating system, hardware, etc.
Cost: at least $30 / month
Strengths: Great performance; scaling; security; backups; tailored services.
Typical scenarios: Managed hosting is typically used for hosting business websites.
Also known as a dynamic virtual private servers (VPS) is a virtual machine sold as a service.
Cost: varies from $0 to unlimited depending on your own requirement
Strengths: High flexibility; scaling
Weaknesses: You have to maintain the website by yourself (upgrade, backup, etc)
Typical scenarios: Developers and enterprises (with developers) that want flexible control and full customization of the website.
Real Server Hosting
Cost: you need to buy the dedicated real server machine (several thousand dollars) and pay for the monthly maintenance (a few hundred dollars).
Strengths: Total control
Weakness: You have to maintain the website and even the hardware. Hard to scale
Typical scenarios: Enterprises host the real server machines and websites inside the company IT.