Rules:
*You can teleport into and out of it at will
*It has a couple of plug sockets and can connect to internet from the region you teleported in from
*You can take objects and people with you
*As already stated, it is 3m^3. The walls are plain plaster with a light in the middle of the ceiling. The pocket dimension is topologically toroidal, so if there weren’t walls and a ceiling/floor (which you can actually destroy) you would loop if you went more than 3m in any direction. Gravity, then, is artificial and can be altered to anywhere from 0 to 2g from a dial on the wall.
Can I only teleport back to where I teleported in from, or can I teleport out of the cube to anywhere I want?
Sorry, I should have specified. The former.
How is the pocket dimension anchored? If I was on a plane and teleported to my pocket dimension, and then came back 5 minutes later, would I still be in the plane? Or would I be where the plane used to be 5 minutes ago?
You would still be on the plane.
After spending a few minutes mulling it over, I’ve realized the only right move is for me to sell the cube to someone more clever than myself.
Don’t just sell it - timeshare that bitch!
That’s arguably clever in itself. You recognise your weakness and adapt to turn a profit.