I have 3 Sky Mobile sims for my wife and 2 kids. They've been 50% off for 12 months so 10gb has been £5 per month each. The deal was coming to an end meaning they would go up to £10 per month each.
The first deal I was offered was 25% off for 12 months making it £7.50 each for 12 months.
But then I was offered a better deal. If I bought out a basic Nokia 105 phone I could have 50% off for 3 years. I could either add the cost of the phone to the contract at 66p per month, or just pay £22 up front. After doing the maths I decided to pay upfront for 3 phones and now have 3 more years of 10gb for £5 per month.
In addition, I'll be getting an extra free sim for my iPad with 100mb per month to which I can transfer data from our Sky piggy bank as needed. This is free for 3 years also.
I think it's a great deal, and compensated in part for the unavailable offer I got from Sky in the post for a 2Tb ipad pro M1 for £20 per month.