So if $1 per 512 stick is the going rate at the factory door.. why is it £7 ($15) in the shops?

That's a total mark-up of 1500%

I would guess that's the price of the chip itself, and the added markup is the result of a snowball effect as it passes from hand to hand; first to a company that mounts the chip on a board and brands it, then to a distributor, then finally to a retail store. Add shipping/handling costs and a modest amount of profit to each movement of the chip, and 1500% total markup seems reasonable.

First of all, that's 512 megabits (Mb) not megabytes (MB). So to get 512MB you would need to put 8 512Mb on a stick ($8). Add the actual stick and soldering (~$1) and you end up with a stick price of ~$9. Packaging, postage (per stick), etc might add another $1 to the price.

So, $10 by the time it reaches the shop, $15 by the time you bought it... which doesn't mean $5 profit for the shop, just $5 INCOME, from which their own expenses have to come out of.

I am not a financial analyst, accountant or even shop clerk... but even I realise the factor price of a basic *component* should not be compared to the shop price of a finished *product*.