Recommendations for outdoor storage shed

True I'm not trying to build a house lol.

So are you saying the 4-bys should be 3 feet under ground level? That would mean I'd need some kind of excavating equipment? I'll hit YouTube for more info and visuals.
The hole diggers that work with your hands. Muscle power. Thats what I use at age 75. Call Lowe's, probably $50/ Or borrrow a pair form someone. Yea put them in the dirt so a 60-70 mph wind does not blow the bldg. away. Call a local building supply co.and just get prices on the lumber and tin. Then add price for nails/screws. Nothing is cheap but it is cheap when you do it!