Pricewise, the Fantom is the best deal.
You can buy one off ebay for 250
Cheap laptop for under 100
Economic car battery for 30
You total is 380USD. That's a good deal. I wouldn't use anything less than a car battery. Powersupplies won't give out enough amps for the initial pull. I guess you could find something for true labratory use for about 1 grand. A car battery will give you enough dyno time to do about 50 runs before the power actually goes down.