Prebuilt portable garage shed?

I built a 12x24 storage building a couple years ago, for the grand total of $2600
I dug 2' deep pillars about 2 x 2' made footers and added re-bar. Hand mixed bag cement and poured them all level with each other.
On top of the pillars, added treated 6x6" lumber, covered the 6x6's with black plastic for a vapor barrier, then decked it with 2x12" treated lumber.
Basically like building a super strong deck on a house.
Took me about a week, after work to do this, even had my 10 year old kid running the nail gun.
I then bought a u-assemble it kit from Sheds-for-Less for $1800, me and my buddy had it done in a weekend to put the building itself together.
It would have went faster but we went down to the local bar n grill for lunch on Saturday and no work got done the rest of the first day.
This was pre-covid prices.