Let's play "take whatever you have on hand, stick it in a box, and make it drive around". This specific robot currently is housed within a Cisco ASA 5505 case, driven by 2 NEMA 17 stepper motors, and eventually a mcu or three. Implementation has just begun.
Components
2×
DRV8825 Stepper Motor Drivers
2×
NEMA 17 Stepper Motors
8×
M3 screws
2×
6" Lawnmower Wheels
From Harbor Freight
1×
Cisco ASA5505 Chassis
Or any square metal box. Equipment exposed to lightning can be had for cheap.