Dry Laid stone foundation?

The skill has mostly been lost. The small number of truley experienced and skilled command a premium labor rate and it's applied mostly to Landscaping walls.

I'm sure you would have a tough time getting an inspector to sign off on one.

I suspect it would cost twice or more to build Vs poured or block.

I would have to have an Engineer sign off in my area to even be considered and then have a substantial "battle" to have the City accept my plans for such.

You might inquire with your local Building Safety dept engineers to get their perspective on it - since they are the ones that would accept or deny.

Good Luck.

It is cost prohibitive. It would be easier to pour footers or piles and do a dry stack facade and hide the footer or piles giving the appearance of dry stack foundation. it would also be quicker and use less stone $$$$. Less stone is less time spent dry stacking. You are talking about a lot of stone below the frost line. If you just have money to burn I would say go for it, Other wise put the money elsewhere in the home. cut your costs.

If it's just a wooden shed, layed on flags to spread any load / weight would suffice. Ideally, lay flags level on compacted ground, then lay 2 or 3 (depending on size of shed) lengths of timber on top to place shed on, separating shed from timbers with polythene or similar to stop moisture reaching shed base. Laying a concrete foundation would be excessive, unless the ground was really soft. £1000.00 sounds horribly expensive ! You don't say where you live.