It's not free, but SigmaZone has decent software packages at prices ~ $500 and under. You can pick the package(s) that have what you need and no extra baggage. I have used the Quantum XL package and like it. These are for single-user, perpetual licenses, and are Excel add-ins, so they are fairly easy to learn.
Otherwise you would have to go with R or Python. They are free, but are based on command language and are difficult to learn.