If you're looking for affordable, free VSTis can't be beaten.
See this thread for a couple of links to organ VSTis.
https://www.keyboardforums.com/threads/changing-the-voice-of-a-roland-fp30.27415/
Roland Sound Canvas has some great sounds but I dunno how tweakable they are and what FX can be added. I'm certain it has at least a couple of Hammond Voices but depending on what you want to play and whether or not you need full leslie and drawbar emulation it would probably be disappointing for you.
Do a forum search on "Hammond" and "B3" and you'll probably come up with dozens of soft synth and and few module and keyboard solutions that would work just fine.
Also, there's a good chance Delaware Dave will stop in and mention a few of his favorites as well.
For some people, a good Hammond Sound is like Sex. Can't be duplicated for cheap
Gary