You could see different prices for the same product, as it could be listed by many Sellers.
Installation and demo are offered for certain items by sellers through the brand or an authorised service provider. Please check the individual product page to see if these services are offered for the item.
Items marked as ‘Preorder’ or ‘Forthcoming’ are expected to be released soon and you can pre-book them with sellers. Such items will be shipped after their official release by the seller with whom you’ve pre-booked them.