#6 Rayo Vallecano (Gael Kakuta, 3 mil euros)
Gael Kakuta is a 27-year-old DR Congo international, who plays as a left winger. He started his senior career in Chelsea in 2009 and played only six matches for them until his departure in 2015 to Sevilla. For Sevilla, he played for only one season and then joined Hebei China Fortune, who sent him on a number of loan spells themselves.
Kakuta has now been signed by Rayo Vallecano for 3 mil euros. This is his second stint in Rayo Vallecano after his one year loan at the club in the 2014-15 season. He is an experienced contender with 199 appearances in his club career and finally, at Rayo, he has a good chance to prove his worth.
Jose Pozo from UD Almeria was Rayo's previous highest transfer, which included a sum of 1.3 million euros.