Google search appliance has been discontinued recently. Check out Google search appliance (GSA) pricing in this blog.
Google search appliance (GSA) pricing below
Queries per day
Search Response time
Phonebook whos who
SAP Enterprise portal
Corporate intranet site
Less than 1 second
This information has been extracted from the document titled Improving Your ROI with Google Enterprise Search.
This particular table showcases the Google search appliance pricing