SSL apparently boosts SEO with Google.
I’m going to add SSL to a site, but I’m not sure which SSL to add.
I found an SSL source called DigiCert that claims there are different levels and/or quality of SSL, but I can’t tell if this is true or just DigiCert hype. See https://www.digicert.com/which-ssl-cert-for-seo-ranking-boost.htm
SSL does affect SEO to a small degree and there are different levels of SSL, however it is unclear whether one version of SSL would achieve a higher ranking than another. It’s a relatively small signal in any case so you shouldn’t expect to leap up the rankings simply because you add SSL.
I added SSL for free via CloudFlare that took just a few minutes to set up and at the time I think my site jumped about three places within a couple of days. Since then it has gone up and down though for other normal reasons. I don’t know what your site is like but if you are selling online or handling visitor information SSL is obviously good practice but also helps with conversions.
EDIT: I’ve just looked at those prices and don’t think you need to spend anything like that. If you don’t want to go the CloudFlare route check out https://letsencrypt.org
Google has noted that security is important, and may play a bigger role in SEO in the future, but yes, it’s small now.
I also use CloudFlare, as do many of the RW add-on developers.
If you do want to go full encryption (which CloudFlare can also handle), here’s another option: https://www.namecheap.com/security/ssl-certificates.aspx
A caution: those certs are less widely accepted, I think someone mentioned it was like 99.2% of sites as opposed to 99.6%, or something small like that.