Amazon AWS is the leader in Cloud provider marketspace. AWS started out with IaaS but have also become a PaaS player now.  Amazon’s services extends Computing, Storage, Database, Analytics and Application services. There are multiple granular services under each of the above categories. The best way to get familiar with the cloud services is by trying them out. AWS has an excellent 1 year free tier program where users can try AWS services. The free subscription is with the smallest performance VM and it cannot be used for business purposes, but its a great tool to experiment and get familiar. I could not find the free option with Google compute engine. With Microsoft Azure, they have 1 month trial option.