Try monetising your forum and you may discover it’s hard to raise >$40 a month. Unfortunately in this day and age people expect these communities to be free.
By minimising cost you can make it a much more sustainable concern putting less pressure on your revenues.
This all depends how busy the forum is, who your audience is and the subject matter of course. You may also find unique ways to monetise due to specifics of your community.
Your first step here should probably be to fire up a $5 droplet at DigitalOcean and give the install a shot. You will be able to run multiple plugins and make mistakes with little to no risk. Pretty quickly you’re going to learn if self-hosting is for you, and if not have some idea of how much you’re willing to pay others to do it.
That $5 is prorated, so if you decide after 24hrs the exercise was a mistake you’re going to be out of pocket to the tune of… $0.16
Mailgun will be free below 10k emails/month as long as you don’t do anything daft, it’s very low-risk and will help you learn about the platform as you go.
Digital Ocean is great for taking a test run, but get into trouble self managing this and all the time you’ll invest to get it tuned to your needs and $100 per month starts sounding really good. I had an instance go bad and the backup wasn’t even working to restore.
Digital ocean has been working for us - Low startup and has a plan that includes Discourse along with scale-ability as resources are needed. We use their WAF and backup instances.
I can usually help people out for $100-300 when they get in the weeds with self-hosting. Self-hosting also allows you to use plugins that would require moving to discourse.org’s Enterprise plan. I have done installs for several hundred self-hosters and though I do command-line upgrades for some of them, a whole bunch of them just keep going for more than a year before they need my help again.