Your options are to buy two certificates (single-entity, one per sub-domain), a
multi-domain certificate (using Subject Alternative Names for the domains), or
a wildcard certificate (securing *.somedomain.tld). Some of the cheapest certs
that are NOT LetsEncrypt can be found at Namecheap - aroun
I wrote about this a few weeks ago. I have a website hanging at Google but
hosted at Network Solutions. It is a 100 percent personal site that I use to
post stuff to friends, and business needs. It is not for marketing and in fact
I don't want anybody uninvited to view it and have a robots.txt