Melody,
You don’t necessarily need expensive software to do Monte Carlo simulations (though it depends what you classify as “expensive”!).
You can do MC simulations using Excel (though I’m not a fan of Excel!).
I use an old version of Mathcad (unfortunately, PTC, who own Mathcad, now insist on an annual subscription for newer versions – and you can’t buy the older versions alone!).
I also use a home version of MATLAB - price ~ £100 (100 UK pounds) – made by the Mathworks.
There are lots of You Tube examples of MC simulation. A simple example is shown at https://www.youtube.com/watch?v=VJTFfIqO4TU for example.