I doubt Discourse will run on a $5 VPS. The last time I checked its crashes on 512MB RAM, needs at least 1GB just to start. Have the minimum requirements changed? 1GB minimum and 2GB is recommended by Discourse itself.
Discourse is also not easy to setup, its quite involved and complex and you need some Ruby and systems expertise. Infact I think Discourse only supports Docker installs. So you need to know Docker too.
Given the complexity you should be pretty comfortable with Ruby to run it with any amount of confidence. The hosted option seems much better than trying to run it yourself.
I did just run across a cloud provider with $5 VMs with 1 GB of RAM (somewhere), but the last time I checked it's at least $10 per month to host Discourse on DigitalOcean or similar.
Discourse is also not easy to setup, its quite involved and complex and you need some Ruby and systems expertise. Infact I think Discourse only supports Docker installs. So you need to know Docker too.
Given the complexity you should be pretty comfortable with Ruby to run it with any amount of confidence. The hosted option seems much better than trying to run it yourself.