Plusnet's £70 cashback offer does reduce the total 18-month cost to £289.82, which brings the rate down to around £16 per month – but that's still marginally higher than the Post Office's rate.
You can however expect roughly the same download speeds from both services; Plusnet offers 10Mbps while the Post Office offers 11Mbps. Both services also promise not to raise rates within the contract period, though after which, prices increase to the standard rate of £30.98 and £30 for Plusnet and the Post Office, respectively.
You can get faster fibre broadband packages from the Post Office if you prefer, starting at £20.90 per month for 38Mbps. View the Post Office's broadband deals here.
We're also rounding up the best broadband deals of the month across all major UK providers, so check that out if you want a full view of the strongest deals out there right now.
You can also view the best deals available in your area using our tool below – just type in your postcode and then click 'filter your results' to narrow down your results.