Assuming your landing pages have on average 500 words:
automatic translation of each landing page will cost approximately 0.12€ (0.135$)
human correction of the automatic translation will cost approximately 10€ (11.3$) per landing page. Human cost varies depending what languages are involved.
Note: A common usecase is to go with the human correction on the key landing pages only – for instance the marketing content. For such use case you need a system which can manage this process for the whole website, where parts are translated by a machine and some other parts are corrected by a human.