Let's Encrypt SSL Certificates
Many hosting providers have integrated the use of the free Let's Encrypt SSL certificates now. In many cases the SSL certificates are installed and renewed automaticly.
In some cases you may be able to download the certificates from your provider, and use them for your development environment, you just have to remember to download them again every three months.
It is no problem to use the local developement certificates generated by this site on you local machine, and use other, "real world" certificates on the same, but "live" domain. The advantage of using the certificates from this site is that they are valid for 5 years. Long enough to finish a project.
Get a Let's Encrypt Certificate for Local Development
If you can't use or get the certificates from your hosting provider, you can download Let's Encrypt certificates from here: Free Wildcard SSL Certificates Let's Encrypt
You will need access to the site to upload some stuff, and possibly the DNS entries of the site, if you want to use wild card certificates.
Once you have the certificates, you can use them on your local server too!