I have 4 servers. Nothing enterprise-grade - a couple of app servers, a database box, and a staging machine. Datadog was costing me $60/month to show me CPU graphs and disk usage. That felt wrong. So I tested alternatives. Grafana + Prometheus was the obvious choice, but the stack itself uses 500MB+ of RAM. On a $4/mo VPS with 2GB total, that's 25% of my resources just for monitoring. Then I found Beszel. Its agent uses less than 10MB of RAM. The entire monitoring stack - hub and agents across 4 servers - runs on a $3/mo server and barely touches 50MB. Here's what happened when I switched.…