Sky is offering 12 months' free and a £100 M&S voucher to new customers who sign up for its Unlimited Broadband & Calls package online.
For a limited time only, the service provider is running the special offer on its entry-level double-play broadband bundle.
Ordinarily, customers pay £7.50 per month plus line rental for Sky Unlimited Broadband & Calls, which is available on a 12-month contract.
But with online subscribers benefiting from one year's free internet services, they can save £90 during this introductory discount period.
For the first 12 months, all customers have to pay for is line rental, which is priced at £16.40 per month.
The £100 M&S voucher is available to new customers who register for Sky Unlimited Broadband & Calls over the internet.
It can be used to make savings in M&S stores across the UK.
The broadband deal offers download speeds of up to 17Mb with no usage cap. This means subscribers can consume as much data as they like over the course of the month.
Customers also receive a free Sky Hub wireless router - which offers connectivity throughout the home - along with unlimited Wi-Fi minutes and weekend calls to UK landlines.
Sky is also giving consumers the chance to save money when signing up for its super-fast fibre broadband deals.
The firm's Sky Fibre Unlimited broadband deal is available with a 50 per cent discount for six months, allowing customers to save £60 in total.
The half-price package - which offers up to 38Mb download speeds with unlimited data - is priced at £10 per month plus line rental during the introductory discount period.
This rises to £20 per month plus line rental thereafter.
Again, subscribers receive a free wireless router, weekend calls and free Wi-Fi minutes as part of their deal.