First, please don't use forums to add extra links that have nothing to do with the subject (for SEO or whatever else => I removed it).
To answer this post, soundfonts are commonly free to use. This has become the purpose of the format: providing free material so that everybody can use it. The quality is sometimes of uneven quality but on this website you can focus on how the soundfonts are rated.
Some soundfonts might not be free for a commercial use. Please see with the author first.