SMARTY's coverage is powered by Three, which also has an unlimited SIM plan for £20 per month on now, but it's a 24-month commitment. SMARTY's offer is a 1-month plan which you can cancel at any time.
We've curated all the best SIM-only plans of the month all in one place here. Our comparison tool below also lets you browse through all SIM-only deals across the web, from all networks.
SIM-only Deals - All Networks