In return, you'll get an average speed of 36Mb, more than enough for everyday streaming and browsing the web.
Unfortunately, you won't be able to get any rewards on that deal, but stepping up just £5 a month will secure a £100 BT Rewards card, thanks to Mastercard. This will also up your total saving to a staggering £144.
For the full £125, you'll need to go for at least the Superfast Fibre 2 at £34.99, but this should get you speeds of around 67Mb.
The Reward Card will come pre-loaded with funds, ready for you to use anywhere you see a Mastercard logo. This gives you the ultimate freedom to spend this money as you choose (we'd recommend Cyber Monday tech!).
As always, it's worth checking what sort of speeds BT will actually be offering in your area. Check what the service will be like on the BT website.
If you're looking for more where that came from, see more of our best broadband deals.