She doesn't really pay for them so she buys more than she can wear. Farfetch gives her coupons to redeem then on the site.
I don't know why anyone would buy from Farfetch to be honest because their prices are way too high and change according to size or the store the product comes from. I was checking the prices for the Hangisi pumps and most of the sizes are sold there around 1450 euro
, when in every other site like louisaviaroma, even on the manolo blahnik website, the price is 950 euro! That applies to almost everything they sell.