Hi, I'm looking for a single-board like a Raspberry Pi with real Gigabit Ethernet (not ethernet on USB like RPi do) and SATA connection with almost same price. I want to use it for downloading big files with fiber.
I don't think you will find a raspberry PI competitor for the $35 price that has gigabit and SATA. There are some similar form factor with gigabit but they are $75+ Your best bet would be to go to a pawn shop, thrift shop or similar and buy an old desktop.
The only candidate I can find that is close to your desire is the RockPro64 which has gigabit and PCIe x4. That would be enough for SATA.