About a year ago, Google started flagging unencrypted (available using HTTP as opposed to HTTPS) websites as “Not Secure” in the Chrome address bar. They have also started taking into account whether or not a site has HTTPS for purposes of search rankings. In other words, lack of HTTPS will affect your SEO.
Side note: HTTPS encryption is frequently referred to as SSL and the certificates that allow this are almost always referred to as “SSL certificates”, but this term is not technically accurate any more. SSL was the original cryptographic protocol used for HTTPS but it is obsolete and not considered secure any longer. TLS is what’s used for HTTPS encryption now, but the term “SSL” stuck.
For years, the general consensus was that you needed HTTPS for sites where you entered a credit card or things like that, but that for general information sites (like blogs) there was no need to encrypt the information. That consensus has changed over the last few years.
Most people have historically bought “SSL certificates” from a vendor like GoDaddy with prices starting around $75/year. A few years ago, a service called Let’s Encrypt was introduced by the Internet Security Research Group. Basically – they offer free certificates to encourage people to use HTTPS.
It sounds too good to be true and I was skeptical when I first heard about it, but it’s legitimate. I’ve been using their certificates for about a year. I’ve used them for websites running in AWS and Azure. There’s a little bit of a learning curve in learning how to get them to issue the certificates for you but once you figure it out, you won’t ever need to pay for certificates any more. (Blatant commercial message – we can help you with this learning curve.)