gratis
Definitions
Given or done for nothing; free of charge.
Without making any payment; gratuitously.
Examples
The museum offers admission gratis to all visitors on the first Sunday of every month.
The software company provided a gratis upgrade to all users who had purchased the previous version.
He was happy to offer his legal advice gratis to those who could not afford a lawyer.
Synonyms
free complimentary pro bono costless gratuitous unpaid charitable