An eBay flash sale has just started, and will run until 10pm tonight. See https://www.facebook.com/eBay.co.uk (https://www.facebook.com/eBay.co.uk)
Code is CUKFLASH
It's 20% off any purchase or collection of purchases in you shopping basket. Minimum spend £20. Max discount £50 ie £250 spend or more gets you £50 off.
You must pay by Paypal before 10pm, so either "Buy It Now" or auction ending before 10pm.
Only one transaction, so you can't get £12 off a £60 purchase then go back later for another discount, even though you've claimed less than the £50 max discount.
ETA: You enter the code in Paypal just before confirming your purchase.