Given that Tableau charges $42 US per user, per month, I am not surprised you are looking to find a cheaper solution. The price reflects the time taken to produce the programs/routines to display the pretty graphics, all of which can be replicated using free software (Libre Office) or existing commercial products such as Microsoft Office.
Programming experience with C++ or Visual Basic will be an advantage as extensive use of macro functions will be required to produce the custom displays.
Visualisation software can be useful in highlighting hidden links within data sets such as the correlation between the phases of the moon and an increase in crime, or increased admissions of psychiatric patients. The danger is that these highlighted links look very plausible within the limits of a single data set, or even a combination of sets. This is because the human mind looks for patterns, even in completely random data.
There are links in the above mentioned examples, but not for the reasons that are commonly assumed.
A browse through some articles on unconscious psychological bias and the deliberate misrepresentation of data may prove fruitful in assisting you to come to the conclusion that you really don't need to use this software at all, unless you are in the business of deliberately deceiving people or obfuscating results.