Tableau Public

Can you learn basics of Tableau with Tableau Public which is free?

Absolutely. The basic difference between Tableau Desktop & Tableau Public is that Desktop version can connect to different number of data sources like Oracle, mysql, salesforce, spark Tables, hadoop, text files and many others whereas Public can only connect to text files. Also there is limit on number of records you can pull in. Also you can only save your visualization on Tableau public server which can be downloaded by anyone so unless there's some confidential data you are working with Tableau public cannot be used. Apart from that the functionality is almost same. Tableau Public is a great tool to start learning data visualization.