Companies like (and especially) sky have always done this. IE 'Subscribe for only £9.99' However there is then a compulsory installation fee of £50 and oh actually the advert was specifically written to make you think the word free meant feeless and internet is extra, oh and you need a TV package to be able to watch anything... And don't forget the free receiver never belongs to you and the contract states it is on a rental agreement and it must be returned when you stop paying for the overpriced service but the moment it goes wrong they deny it's their property and quote rediculous fees for someone to come look at it, oh and phone up to cancel and they pass you round from pillar to post for 2 hours until you mention to them you rang a freephone number and not their premium rate customer service line...I can understand that thinking.
They seem to sneak things in a lot on free, cheap deals that have been around for yonks, a modern practice and I will not say which country I think it might stem from (Monetarize everything ethos?)
Worm on the hook and reel in the customers who are too silly to realise what's happening to them.
One only has to look at their scrap policy to see why they have to charge so much.