If you want a contract with unlimited data then you don't have a lot of options. Your only choices are Three or Virgin, and normally the price difference is only £2 if you're signing on for a 12 month contract. Well Three would like to make your decision easier on Black Friday, and has knocked money off its standard 12-month unlimited data plan. Instead of costing £27 a month you'll be able to get it for £20.
£27 a month normally gets you unlimited everything, including tethering, but waiting just three days can save you £84 over the course of a year. It's not as cheap as some of the old unlimited data deals (I still pay £17 a month), but very few of them were so generous with the non-data allowances. It also comes with the usual Three perks like free roaming in 71 countries, the zero-rate Go Binge, and access to Wuntu deals. Three has promised the price will stick for the duration of the contract, but made no promises about what happens after 12 months.
Three is also offering the iPhone X on the unlimited data plan, for £53 a month, with £99 upfront, shaving a total of £480 off the usual cost. If Apple isn't your jam, you can get the Huwei P20 Pro with the same allowances for just £40 a month, with £29 upfront. Saving you £480 in the process.
If that's not for you there are other deals that will be available, including the Samsung Galaxy S9 for £30 a month, with £79 upfront and 30GB of monthly data. Likewise if you get a Pay-As-You-Go Xiaomi Mi8 or RedMi 6A Three will give you a free Xiaomi Band 3 and a £20 'All-in-one' add-on for just £10. That gets you 12GB of data, 3,000 minutes, and 3,000 texts to use as you like - within the limits imposed by the terms and conditions.
These deals don't go live until Friday (23rd), but once they're up you'll be able to find them in-store and on the Three website.