Don't buy anything.
You need 2 small screw drivers to open it. But first you need to unscrew one screw in the middle.
Start on one side with a SD and lift it just a bit, and then use another SD on the same side. Then live them in the hoes that you'll see there and use a bit of hand work on the perpendicular side where the ETH port is.
It really isn't an engineering task. Just do it.