Real Madrid CF missed out on Kylian Mbappe this summer after Paris Saint-Germain refused to accept any of their bids to purchase the forward. It is widely believed that the Frenchman will join the Spanish giants on a "free transfer" next season, but the fact is, the move will still come at a massive cost.

Los Blancos are hoping to lock down Mbappe on a pre-contract agreement by January, when he will be legally allowed to start talks with other clubs. However, there are still a few obstacles that stand in the way.

First of all, PSG are believed to be determined to keep Mbappe, and will be offering him a new deal even after he has rejected all their previous offers for an extension. PSG had also rejected Real Madrid's last minute bid, which is believed to have reached up to 200 million euros. The French side took the risk of possibly losing the player on a free transfer next season, instead of cashing in on him now.

The 22-year-old has made it clear that he wants to join Real Madrid, but anything can happen in the next few months and PSG might be able to sway him.

Even if that does not happen, Mbappe will have some leverage when he officially starts talks with Real Madrid. Even though he will be available on a free transfer, Mbappe will likely ask for a sizeable signing bonus. According to Marca, this amount may be somewhere in the region of €80 million.

As such, Mbappe will be free to leave PSG, but it will not necessarily be for "free." Real Madrid will still be expected to fork out a large sum, but it will still be a bargain compared to what they would have spent this summer. However, the player's salary is another story altogether. Florentino Perez will have to handle the negotiations wisely in order to avoid being tied down to another long term deal with a very expensive player like what happened to the likes of Gareth Bale and Eden Hazard.

Lionel Messi and Kylian Mbappe
Lionel Messi and Kylian Mbappe AFP / Bertrand GUAY