Recommendations for outdoor storage shed

8x10 resin shed , from Costco or Sam's club. Roughly $800.
I'm looking at a 10x20, about $3500, plus whatever a slab costs.
There's always a used container, bur that's out of your price range. I saw an add for 20 and 40 footers at a reasonable price, but the price became very not-so-reasonable when they found out where I wanted it. Socal, fine, cheap. 125 miles from nearest, (vegas) about double, about $5k for a 40, delivered.