Agent37 runs isolated cloud sandboxes for teams that want one AI agent per customer without operating the machines. Each sandbox can host Hermes, OpenClaw, Claude Code, Codex, or a custom image, keep its files across sleep and restart, and connect to apps such as Slack, Gmail, and GitHub. This launch puts a number on sandbox list prices. A 2 vCPU, 4 GB RAM sandbox with 4 GB of disk is $4.76 if it runs every minute of a 730-hour month. Agent37's comparison lists the same shape at $248.78 on Vercel, $145.28 on Cloudflare, and $120.89 on Daytona. Billing is a prepaid balance, metered by the minute while the sandbox is awake, with no subscription. Stop it or turn on auto-sleep and the charge falls to disk only, $0.36 a month for 4 GB. New accounts get a $5 credit after a card is added. The company says it will refund the difference if you find a cheaper sandbox. On its Hacker News launch it said customers average $0.37 a month per sandbox, which matches intermittent use rather than a box left on all month. Founder Vishnu Krishnaprasad is in Y Combinator's Fall 2026 batch. He was a senior software engineer at Amazon and an engineering manager at Quantcast, and he has a master's from Carnegie Mellon. He has described the rate as hosts rented from Hetzner and OVH instead of the large clouds, gVisor isolation so sandboxes share memory rather than each reserving a full VM, and packing for agents that burst on CPU and then wait. gVisor does not run Docker-in-Docker, so those jobs use a full VM at a higher price. In the YC post, Boon said a Hermes agent for nonprofit grants fell from $85 a month to $4.94, and ETEC+ said it moved more than 30 clients onto a branded product in six days.