25% off Everything including Sale! at Toms at TOMS (UK)
On TOMS, the shoe website, you can use a promo code on sale items to stack a discount:
Use the discount code: GETTOMS
You can get these pink canvas shoes on sale from £40 to £16. Add to basket.
Then... Add another of something else:
For example, these black synthetic trim shoes also on sale from £44 to £17.60.
Go to checkout, add the discount code GETTOMS and you get an extra 25% off:
It also comes with free delivery!
This post has been updated by Tom to give examples