The cheapest landline phone service is £11.73 with BT, which includes their Standard Line Rental plan and a discount for customers who take just a phone line and don't have fixed line broadband from BT or any other provider.
For people living in Hull, KCOM offer a landline phone service for £11.99 for those who pay by Direct Debit, or £12.49 for those who need to pay by cash or by cheque.