I don't believe there are any publicly trusted certificate authorities (including Let's Encrypt) that offer free code signing certificates. As I understand it, this is partly because code signing certs can only be tied to a person or business identity (as opposed to more common web PKI certificates that are domain validated). So it costs much more in man-power for a CA to validate those identities.
Though given the number of software systems placing increasing emphasis on code-signing, I really wish the CA/B would come up with a DV equivalent for code-signing certs. It's a huge barrier for individual and small team developers, particularly those doing free or open source work.
It also makes more sense to me from a user perspective. If I'm downloading some app, unless it's made by a well known software company, I rarely know who the developer actually is. So if the signature on the binary is tied to "Jane Doe" rather than "superawesomesoftware.com", how does that help me? In some cases, the code signing cert for even well known companies is actually held by some lesser known parent corporation which is even more confusing. I'd much rather see that the signature matches the site I got the software from.