Total cost so far ... CAD $193

In case anyone would like to build a similar robot; here is my list of materials.

Material purchased:

Prices in Canadian Dollars

$15x2=$30 - NEMA 17 stepper motor, 1.5A, bipolar (x2)

$4.5x2=$9 - NEMA 17 stepper motor mounting bracket (x2)

$3.5x2=$7 - 5mm Brass Hex Mounting Hub (to couple NEMA 17 and BaneBots wheel together) (x2)

$4x2=$8 - BaneBots Wheel, 2-3/8" x 0.4", 1/2" Hex Mount, 30A, Black/Green (x2)

$1x2=$2 - A4988 driver (x2)

$13 - HDPE sheet (1/4" inch thick) for chassis

$4 - M3 x 20mm Hex Standoff Mounting Kit (10pk) To mount Arduino etc to chassis

$15 - Screws and Nuts Mounting Kit

$90 - Raspberry Pi 4

$2 - GY521 (MPU6050) IMU

$4x2=$8 - GY9833 (AD9833) PWM generator to convert RPI command into PWM to drive A4988 stepper motor drives

MISC (total <$5):

100 uF capacitors for A4988 and motor connection

Fuse (for Arduino protection)

Fuse holder

LED lights (for debug and robot status display)

Material already at hand:

18650 batteries (salvaged from an old laptop)

Breadboard

18650 battery holders