Don't miss out on the fact that you can easily merge multiple .csv files together using the copy command in Windows command prompt.
Simply press CTRL + SHIFT and right click in the folder containing your .csv files, and select 'Open command window here'. Then simply enter the copy command followed by a wildcard search for .csv files and the name of the file you want the data to be combined in.
The result will be a single file containing all of the data in your source files. If the source files don't all have the same heading you may have some additional work to do aligning the data.