I have an Xbox 360 controller and I want to know how I can pair it with a Gameshell
Unless it’s a corded one, I wouldn’t bother. Xbox 360 wireless controllers use their own proprietary wireless signal that isn’t blue tooth.
If you want to use a wireless controller, you will need to buy a Xbox 360 wireless to USB adaptor; normally for PC. This will then need go be plugged into the gameshell via a USB OTG cable, which will be a big old mess of cables.
Likewise, with a corded Xbox 360, you will need to plug it into a USB otg adapter.
Alternatively, you could use a wireless controller that isn’t an Xbox 360.
How expensive are bluetooth controllers?
I guess? I’ve never owned one, but I’d assume it would. I can’t guarantee anything. Probably a more popular choice would be an 8bitdo controller. That’s generally considered the retro gamer’s controller of choice.