A cart and spare parts for 30sp?
I'm good, but not that good.
I think you're off by a factor of 10 chief, if you're lucky maybe cheaper, but yeah, not that cheap.
So no donkey?
200lb cart, no bridal, no yoke, 15gp spare parts were written in gp too, it's going to be more for one mules can pull. Can carry 1900lbs with one mule pulling, two is ok if they're in tandem. Spare parts, bridal, yoke, hitches between the mules are non-zero costs.