Depends where you are. We paid £8k incl VAT 2-storey, 100sqm footprint, 10 weeks with a flexible end date (which is proving handy after the last 2 storms). Went with a big local company, so they have loads of kit (no pressure to get it back), could accommodate the erect 3 sides for the TF company and then 4th side a few days later and weekly scaff tag check is easy because they’re down the road.
On VAT you can ask them to zero rate the labour costs if you’re self building.