Dell tax on options, I'd wager. If you look at the cost on everything that isn't the base, laptop manufacturers generally add an extra 100% on the retail price of these parts. 200% if you're Apple.

Not sure why you got down voted, Apple's single most insidious, egregious rip off? Memory.

To upgrade your iMac from base 8GB, 4x4 to 32GB is SIX HUNDRED DOLLARS.

Alternatively you can buy this aftermarket from Crucial, same timings, etc, for $139.98.

There is no earthly way that can possibly be justified - a four hundred and thirty per cent mark up on retail prices - even more when you consider the after market lets you keep the original 8GB, whereas your six hundred bucks at apple.com does not.