I want to create a powered single bike wheel , wheelbarrow for hauling gear in the mountains. Would a hub drive be good enough cause its cheaper and wouldn't require a sprocket or chain. Probably plan on loading 150lbs on it just for power assistance going up hill or over logs ect.. thoughts ideas before I start buying parts. Hub wheel kits are around 200 dollars, mid drive are like 400 plus and still would need a battery too. Only need to get maybe 20-30 miles out of it and it would just be power assist mostly.

Super cool idea. Thanks for bring this up. It made me look up what all was available.
https://www.amazon.com/SuperHandy-Electric-Wheelbarrow-Capacity-Exclusive/dp/B07YXCLMWQ
problem is that ebikes like to go faster than a walking pace. You would probably need a external motor and reduction gears like the products in the photos. maybe you could build something with a 20V drill motor with a small bike chain cog in the chuck. and then run a chain around a regular rear wheel.