That was actually I was also looking for – regarding some future projects, so I decided to exted my repository.
The only important thing for me was to use the original pricing table page builder element, so clients could make any changes on their own easily, without breaking anything.
It is only required to insert a single CSS class into the row.
The toggle itsself is HTML & CSS and 1 line of jQuery.
The function to switch the prices is another line of jQuery, so all in all very very leightweight.
Here is how I solved it (sorry for the bad quality, but I think it should be clear how it is designed).
