You can also get a free ssl certificate here: https://www.wotrus.com/english/freessl.htm
However, I would recommend reading if you need to use a free certificate or not, especially some of the answers provided here: https://www.quora.com/Is-there-any-problem-to-use-a-free -certificate-SSL-to-my-domain
"From the buyer's point of view, the value of the CA is determined by its success in placing its root key (browsers and operating systems). Large giants like Microsoft or Mozilla require CAs to go through several administrative and legal procedures before accepting the root keys of their respective CAs, which certainly costs a lot of money. Now, you only imagine that it will not be difficult to think that they are carrying out another illegal activity if all the certificates are provided free of charge."
… and keep in mind that free concerts only field validation, not validation of the company and although I guess most would not notice it, being a computer scientist myself, if I give the details of my credit card on a site that uses a certificate of approval. a supplier that I do not know, I am skeptical about providing my contact information.
In case you want to use a paid SSL, I used RapidSSL myself and asked you to get them from a hosting provider; The host I use has recently added this capability and now has a wide range of SSL certificates from different providers: they are KnownHost and no, I have no affiliation with them , apart from a long-time customer.