Yes. these are free from this location. you can find the latest vmtools from below location.
https://packages.vmware.com/tools/esx/latest/index.html
As vmtools is the package included with the virtual machine and without this Machine cant work. So by default its there, and you can use it. No link i got saying its free .This is just like asking in the Macdonald if " Ham is free in HamBurger " or Is the "Sauce is Free with the Samosa" 
All the best,
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Anjani Kumar
VMware vExpert 2014 . Infrastructure Specialist.
Email ID : Anjani.kumar@vmwareminds.com
Website : http://www.Vmwareminds.com