I did this at the beginning of the year and I have to say £1K isn’t going to go anywhere.
I had a mate who does this sort of thing clear my old plot and hand lay a new 5 X 4m concrete base.
Material and a week of his time was approx £900.
£300 on two skips – you’ll be amazed as to how much 5hite you can end up shifting and waste disposal is bludy expensive now.
I got a custom 4.8 X 3.6m shed from Passmores who were excellent and 1/2 the price of the cheapest local firm (£2.1K). Definitely recommend them, if for no other reason than two blokes erected this beasty in under 3 hours in the rain.
I have spent another £2K or so on further landscaping and what seemed like 5 sq miles of MDF and celotex insulation boards for the shed interior.
I did consider DIY the full build but if you’re anything like me, you’ll need to quadruple any time estimate you may have come up with.
This reminds me, I really must sort out my build snaps