It's not easy to calculate how much the cost will be.

Literal

Costs [subject-が] how-much [question-か] [object-を] calculate [nominalizer-の] [topic-は] easy [copula-ではありません].

~かを算出するのは embeds a question (いくらか = 'how much') as the object of 算出する ('to calculate'). ~のは...容易ではありません means 'it is not easy to.' A formal, polite sentence.