Black Friday is no longer just a day in the calendar that's been forced onto us from America by retailers hungry for money and publicity. It's a series of deals, starting with pre-pre-pre-Black Friday discounts and ending with the Boxing Day sales. Nobody loves Black Friday more than Amazon, which is why it's kicking off festivities early.
Amazon Dash buttons gives you £5 of credit after the first press, and that offer is still valid. So if you buy one and use it you get £3 of Amazon money to spend with Amazon.
Also getting the early Black Friday treatment is Amazon Music Unlimited, which is offering three months access for 99 pence. That offer is valid until 1st December, and is only available for new customers. Obviously if you have Prime you already have access bundled in with the rest of your perks.