You can download and use the Tableau Pubic Version.
That is free and does not require any licencing.
You wont be able to save a local copy of your work though . Also few data connectors are available on the Public version but that shouldn't be a bottleneck.
You can continue learning with the Public Version.
I myself use tableau public version.
Also you can follow my blog Data Vizzes – Turning Data Into Insights where I have started to blog about learning tableau.
Hope you find it useful.