I have a project that has the frontend hosted on Vercel and a small simple service on Render both on the free plans. Vercel analytics is off at the moment because I've hit the limit for the free plan, but as of last week we got 1600-1700 unique visitors daily on average. In the last 30 days, my deployment has had 1.6 million edge requests and consumed about 146GB for fast data transfer. You can probably get away with the free plans for a moderate amount of traffic and then scale as needed.