slightly strange requirement! We have a setup which requires the user to reserve the products they want to buy via an add to cart/checkout system.
So they add what they want to basket, click 'reserve' (checkout, if you like), fill out their name, the date they want to collect it and the store that want to collect it from, then submit it so the site admin can sort it out for collection. No payment involved (though that might come later).
Is this something Exp:resso Store can handle? Effectively skipping the payment bit and submitting a free order, despite the products having prices.