I got my first paying customer. It put me -$12 in the hole

I just hit the milestone every solo founder waits for: my very first paying customer.

Naturally, it immediately cost me money.
Until yesterday, I was running the backend completely free on an old self-hosted home server in my room. Zero server costs, 100% margins.

Then my home internet dropped.

When your app is just a hobby project, an hour of downtime doesn't matter. But the second a stranger pays you real money, you can't afford a dead server while you're troubleshooting a home router.

I scrambled and migrated the entire backend to a paid cloud VPS to ensure 99.9% uptime.
Final tally for launch day:

Revenue: +$3.99
VPS hosting: -$16.00
Net monthly profit: -$12.01

Task failed successfully. At least the proof of concept works.