Ok so the bulk of the saving is just their sale.. this is how I did it;
Tech fleece joggers normally £90 but they are £60 in the sale. So £30 saved 
Then I used UNiDAYS discount as a promo code at check out to save a further 10% off - extra £6 saved 
I then used Jam doughnut to pay and not my card. I use jam doughnut all the time anyway for all my supermarket shopping and save a fortune (Waitrose, M&S, Sainsbury's, Tesco etc - can still use your club card).
Jam doughnut gives me
8.5% cash back on JD so a further saving of 8.5% of £54 which is £4.59 
Total saving on £90 joggers is
£30 + £6 + £4.59 = £40.59
Which is nice because the full price is bloody expensive!! 😀
I love Jam Doughnut and recommend it to everyone. If you haven't got it yet then get it for your supermarket shop at least - the money in there really really adds up.
You can get a free £3 in your pot to begin with if you want by using my code;
I thought you would like the JamDoughnut App. It gives you discounts and instant cashback at 1,000's of shops, restaurants, and supermarkets. Use my referral code VA9Q to get a £3 bonus when you use the app for the 1st time. Download for free: app.jamdoughnut.com/VA9Q
Ask me anything you want if you want more advice about how to be savvy with it! ❤️