AWS vs. self hosting

Now we are considering upgrading our corporate homepage server environment which is already end of life-cycle. everything on server environment is required to renew. (Hardware, OS, SW(DB), firewall service and etc.) we are considering using AWS as well. Questions: 1. which one is less expensive? self hosting vs AWS 2. if AWS is for the answer of question 1, which service is the best one among AWS service? 3. Is it easy to migrate web application based on ASP & IIS to AWS?

Thanks