If you buy in the official market you need to spend real money. Here you spend FG, not real money. You can earn FG selling other game´s items like Team Fortress, CS GO, etc.
FG value round 10$ for 1000fg more less. In official market you can buy 1000p for 45$ more less. With 50% discount you can buy them for 22,5$. With my trade ratio 1p:1.5fg price is 15$ for 1000fg.
I still thinking is a fair offer.