itch.io

You're better off looking into sample-based instruments if you're after a realistic sound. Sites like pianobook & Spitfire LABs are good resources for free sampler instruments. Decentsampler & Kontakt player are popular free formats. Then you'll need a DAW to load these VST plugins & record with them. Really it's better to invest in a basic version of one of the most popular DAWs, than to learn a free one & later relearn a paid one. Currently the most popular DAW for solo producers is Ableton, but I prefer FL Studio & love it. Logic is another popular choice but it is only on Mac. Other fringe choices are Bitwig, Reason, Reaper.