You have to purchase an SSL for each domain unless they are 3rd level.
example tits.whatever.com ass.whatever.com
If they are 3rd level, you can purchase a wildcard ssl certificate.
I have never purchased from this company but they are advertising 4.99 ssl certs. I normally get mine at namecheap.
https://www.ssls.com/lp/4.99-ssl-off...FZeJaQodUIsAjA