The shed itself is a Keter Apex 8x6 (8 feet wide, 6 feet deep). It's a walk-in with floor structure included. Their set up instructions only called for "leveling the dirt" before assembling in place.
So this is about a BETTER ground pad. It's quite standard in construction but often misunderstood or made over-complex. The sloping ground only means that a retaining wall (RW for short) is needed. And if the RW is less than three feet tall, it's considered non-structural as a "garden wall" in most building codes that you can build any way you want. On the other hand, if your RW is three feet or taller, better call an engineer because special reinforcements may be necessary.
Relative Cost (remember this is only about the ground pad, not the shed):
Low to Average
DIY Manpower Needed:
Two strong men (or women! — but just to lift the heavy plate vibrator onto and off of transport)
Special Tools Needed:
Zip Level or water level