Aayu

For free ssl certificate, you can go with Let's encrypt and if you are looking for reliable paid SSL Certificate provider at the lowest price, you can check out once at:- CheapSSLWEB.com.

For the best Code signing certificate, you can check at SignMyCode.com.

I think you can check out these three options:-

CheapSSLWEB.com
Certera.com
ZeroSSL.com

For cheap wildcard ssl certificate, I would recommend to go with CheapSSLWEB.com as I have been using their SSL certificates from last few years and got at the lowest price.