I run two platforms/websites (SaaSHub & LibHunt) that both have 1M+ visits per month. Both products run everything on a single $60 VPS (Linode dedicated CPU 8G

I run two platforms/websites (SaaSHub & LibHunt) that both have 1M+ visits per month. Both products run everything on a single $60 VPS (Linode dedicated CPU 8GB). That includes Ruby on Rails, background queues, Redis (cache and queues) and of course, Postgres. On both machines Postgres takes about 1.3G RAM and not too much of the CPU. CPU utilization is 37% avg and 13% avg. So, yeah, I don't think you need managed and "scalable" Postgres provisioning in most of the cases.