I think $7500 is their net loss. They raised $35,452 on Kickstarter.
https://www.kickstarter.com/projects/583591444/mineservertm-...
Re:$99 Mineserver: The Devil Is in the Details
by dav- on Friday March 18, 2016 @05:24PM
(#11315197)
They raised $35.5k on Kickstarter, and I'm assuming they have spent all of that plus $7.5k out of their own pocket before shipping a single unit.
> But $7500 in the hole is not much cost to start a technology business.
Unless I missed something, it doesn't sound like they paid the developer much at all.