If you’ve got a strong Three signal in your area (check that here with the Ofcom checker), it’s definitely worth checking out this unlimited SIM-only deal.
On a 12 month contract, it’ll deliver unlimited data, unlimited minutes and unlimited texts for a mere £16 per month. That’s £192 overall per year.
Whack the SIM in your existing or new smartphone, or do what I did and get a reconditioned phone, and you’re away. Cheap as chips.