Forgive my ignorance dude but - what is that? The last thing I played Pokemon on was a GameBoy Classic back in the late 90's!
It is the itty bitty Game Boy Micro. It is the smallest Game Boy Nintendo produced, and it is kind of adorable. Here is is next to a TV remote for scale, this thing is tiny.
You can never spend too much on a micro, they're awesome.
Also finding an official leaf green cart is a hell of a task, 90% of eBay is bootlegs, people selling them don't tend to realise. For reference and official one should look like the below:
The indented sticker, and the text on the board above the pins if you tilt the card up being the biggest giveaways on most bootlegs.
I thought I remembered the label being shiny, I had a legit copy of FireRed back in the day. Oh well, I plan on eventually just buying a Flashcart for it anyway, so it's neither here nor there. The games are a bonus, I just wanted the Game Boy.