No clue
Synthesia is p cheap
here's a free piano set up
download this program. it can run as either a VSTi or a standalone program
https://www.plogue.com/products/sforzando/it hosts soundfonts, or .sfz files, of which there are tons of all around the internet for free.
here's a good soundfont piano to start with:
http://ivyaudio.com/Piano-in-162heads up though, soundfonts can be kind of RAM intensive especially that one since it's really well made. there are better options for piano sounds but this one is free and still pretty good.