The sponsor creates the initial offering plan. When the offering plan is approved by the attorney generals office, the sponsor is then permitted to commence with the sale of the condominiums to others. The sponsors role is primary in the creation and ultimate sale of the condominium.
On top of the premium price, they will also require you to pay state and city transfer taxes. These taxes are relatively minimal and commonly paid by the seller not the buyer, but then again it's a sponsor unit. You would be paying them again when you sell. It's likely they won't negotiate their price either. If you go that way, you don't become the "sponsor" as many buyers seem to think. You are a shareholder and subject to the house rules of the Coop like everyone else. The biggest problem is that sponsor units are few and far between but they do exist. Good luck.
I mentioned the sponsor, the sponsor is the developer or the owner of the rental apartment in a building that has converted to sales. These sales do not require a board package and board approval. their prices are at a premium and it is a very fast transaction.