How much will setting up a BT phone line for incoming calls only cost?

You need to phone the BT sales helpline (see your local phone directory) or visit your nearest BT store for current pricing. You can also activate the line you have and get BT to mark it as reduced usage or low usage. Then you only pay for the upkeep of the line and not the standing charge on calls as well. But you'll still need to pay for the ISP you use...

If you already have a line then you'll have to pay for them switching it on and quarterly line rental of £32. If you need a line put in it's over a hundred pounds for the line then your line rental.

If it's a new line that you want then they'll have to come and install it. I had this done and it cost about £120 I think as they had to dig up my driveway to lay the line. It's quite a big job! Is this for an approved burgular alarm? If so there are other ways that are a lot cheaper.

If the line exists already you'll pay a connection charge of around £42. If the line needs to be installed, you will pay £106 for the line and you will probably need to have Call Barring placed on the line. Call BT Sales 0800 800 152 they'll help

I'll bid $1.99/year Seriously, I just gave you a BS answer. Just like anyone else will/can. Call the provider directly if you want real answers to your questions about the cost of their service.