Recommendations for outdoor storage shed

I have the 8x12 metal shed from Lowes.

After 15 years, it's starting to rust out in a few places.

IIRC it was about $350 back then but....

An 8x12 concrete slab, so I didn't have to use wood decking that rots quickly in Florida and creates a substantial rise at the entry (Important if you're wheeling an engine stand or hoist in and out), and can sag.........cost $800.....15 years ago.

I did get three bids and one guy came to the house in a rolls royce (!) wearing a brown workman's uniform with his name on it, and was the low bid.
The high bid was $1200.
...and that was after I had dug a monolithic footer, cleared roots and put up a 1x4 form.