0845 numbers are classed as service numbers and although they won’t usually be included in your inclusive minutes like 0800 numbers are, they won’t cost anywhere near as 09 premium rate numbers cost. This middle ground is why so many SME businesses purchase 0845 numbers and use them for their booking lines and for other purposes.
When you are looking at getting a new contract or pay as you go sim in is very important to check the price of these numbers as they are quite commonly needed to ring things like your bank, the tax office, utility providers etc. You don’t want to go for the cheapest tariff only to find you will be paying excessively for service numbers.
On O2 you will pay 55p per minute if you are on a Pay Monthly contact and 45p per minute if you are on a pay as you go contract. You will be charged a minimum of 1 minute per call.