john west explained :
A pal has offered to build a wooden shed for our allotment.

At some time in the future the shed will most likely need to be moved to a
different plot. It seems a good and inexpensive floor for the shed would be a
Cement one. But we have to rule that out in terms of it being difficult to
move.

What might be a 'lowest' cost, but transportable floor for a wooden shed
please ?

Wood will be fine, but ensure it is raised above the ground so air can
flow under it and well supported. Brick piers are fine for that, with
or without cement. My untreated wooden 12x8, installed 30 years ago,
was installed by me like that and it is absolutely fine.