Why is icloud storage so expensive when google and amazon are free?

An iCloud account also has 5GB of free storage. Most cloud storage services have a free tier and additional storage for an additional fee. iCloud is no different. The pricing and storage plans changes very frequently so even a comparison from a few months ago will be out of date. You'll need to decide what your particular use needs are and choose one or more cloud storage solutions that best meet your particular needs.

You can simply Google "cloud storage price comparison 2015" to get some recent reviews.