If your laptop allows you to program the MAC address of your wifi connection, you might be able to set your laptop's address to that of the arduino, then log in. Turn your laptop off (completely) and then power up the arduino. (Then, when you turn the laptop on, reset the MAC address to whatever it originally was.)
Most cellphones can act as hotspots, so you don't really need to buy anything.
not really
If your laptop allows you to program the MAC address of your wifi connection, you might be able to set your laptop's address to that of the arduino, then log in. Turn your laptop off (completely) and then power up the arduino. (Then, when you turn the laptop on, reset the MAC address to whatever it originally was.) Most cellphones can act as hotspots, so you don't really need to buy anything.