Building a squad to thrive in Europe’s top leagues can take years of careful planning and stability, but Rayo Vallecano’s finances dictate a completely different approach to the transfer market. Last season Los Franjirrojos had one of the smallest budgets in La Liga, second only to Elche. The budget, around €18 million, is dwarfed by the €520 million Real Madrid can rely upon.

Ignoring the discrepancies in Spain’s budgets, Rayo have survived comfortably in La Liga since being promoted in 2011 under José Ramón Sandoval. The club also showed humility and earned the respect of the football world after paying for an 85-year-old widowed woman’s house to save her from eviction in 2014.

Paco Jémez, who replaced Sandoval in 2012, has continued to operate on a shoestring budget as Rayo finished 15th, 8th, 12th and 11th in Spain’s top division.

A look back at Los Franjirrojos’ transfer activity since their arrival in La Liga shows how the Camp de Fútbol de Vallecas resembles something of a revolving door during the transfer window.

After finishing second in the 2010-11 Segunda División campaign Sandoval had to prepare a squad to take on Spain’s elite for the first time since relegation from the top flight in 2003. Sandoval proceeded to sign 14 players on free transfers and loans, financing the deals through right-back Coke’s departure to Sevilla for €1.75 million.

As Blackpool supporters will attest to, trying to blend a squad of new arrivals can have disastrous consequences, but Sandoval’s transfers proved to be incredibly shrewd, both on the pitch and financially.

Michu and Raul Tamúdo signed on free transfers from Celta Vigo and Real Sociedad respectively, while Diego Costa arrived on loan from Atlético Madrid in January. The trio scored a combined 33 league goals while Roberto Trashorras, another singing from Celta Vigo, would go on to be the central figure under incoming manager Jémez with his metronomic passing.

Despite finishing 15th, two points clear of Villarreal in 18th, Sandoval left Rayo to be replaced by Jémez, who previously had two spells at the Camp de Fútbol de Vallecas as a player.

The transfer structure remained the same under Jémez for the 2012-13 season, with a complete overhaul of the squad to replace the outgoing players, including Costa and Tamudo. The only transfer sum Rayo generated was through Michu’s sale to Swansea for €2.5 million in what proved to be one of the biggest bargains across Europe’s major leagues.

Among the new arrivals to impress was Alejandro Domínguez, a diminutive Argentine playmaker, who joined from Valencia after struggling to break into the first-team. At the back Jordi Amat showed his talent following a loan move from Espanyol, while Rayo utilised their academy and promoted striker Léo Baptistão into the first-team squad, with the Brazilian scoring seven goals in his debut season.

Los Franjirrojos were a revelation in Jémez’s first season in charge, finishing 8th above the likes of Sevilla, Getafe and Athletic Bilbao, with 31-year-old midfielder Piti scoring 18 goals. Rather than being able to build on his success, Jémez’s squad was picked apart, requiring another rebuilding job in order to be ready for the 2013-14 season.

Baptistão signed for Atlético in a €7 million deal and due to the nature of the short contracts Rayo offer players Jémez lost key players in Piti and Domínguez on free transfers to Granada and Olympiacos respectively. However Jémez, undeterred by the task, signed Rubén Rochina, Joaquín Larrivey and Alberto Bueno from Blackburn, Atlante and Real Valladolid to replace the goals lost from Piti and Baptistão’s departures.

One of the reasons Rayo’s transfer dealings are so impressive, aside from the pure volume needed in order to compete season to season, is the club’s ability to nurture players with talent who may have fallen off for various reasons.

Take Iago Falqué, for example. The winger was highly rated as a youngster, moving from Real Madrid to Barcelona before joining Juventus. Falqué never made a first-team appearance at any of the clubs and in 2011 he found himself on the move again, joining Tottenham Hotspur.

Falqué joined Rayo on loan from Spurs for the 2013-14 campaign, impressing enough to earn a permanent move to Genoa last season. His form for I Rossoblu was enough to convince Roma to move for the 25-year-old in an €8 million transfer.

Another player given a platform on loan by Rayo in the 2013-14 season was Atlético Madrid midfielder Saúl Ñíguez. Ñíguez was instrumental as Los Franjirrojos finished 12th, and has now broken into Diego Simeone’s squad.

Last season saw a similar story for Jémez and Rayo. Larrivey left to join Celta following just one season and 12 goals. The 30-year-old was one of nine players who left the club on a free transfer.

Rayo continued their policy of foraging around Europe’s bargain basement for new signings, picking up ex-Manchester United striker Manucho and Chelsea winger Gaël Kakuta. Jémez continued to strengthen relations with Madrid neighbours Atlético, loaning Baptistão and former Liverpool left-back Emiliano Insúa from the Vincente Calderón.

Los Franjirrojos also broke with tradition by signing Colombian winger Johan Mojica from Llaneros for €500,000, a rare occasion where Rayo parted with a transfer fee, before immediately loaning the 21-year-old to Real Valladolid.

Again, Jémez’s side comfortably avoided relegation, finishing in 11th place, with Alberto Bueno finishing the season as the second highest Spanish goalscorer in La Liga with 17 goals, one behind Athletic’s Aritz Aduriz.

The turnover at the Camp de Fútbol de Vallecas show no signs of slowing down ahead of Rayo’s fifth consecutive season in La Liga, a run that represents the highest in the club’s history.

Bueno, a prolific scorer for Spain’s youth teams who briefly broke into Real Madrid’s squad, has joined Porto who are looking to close the gap on rivals Benfica in the Primeira Liga. Manucho and former Swansea midfielder Alejandro Pozuelo have both been released, while no fewer than eight players have returned to their parent clubs following loan moves.

Jémez’s recruitment drive is already in full swing, with Bebé’s move from Benfica the most intriguing arrival to date. The 24-year-old is notorious on British shores for a spell with Manchester United, but the Portuguese under-21 international showed pace and power on loan at Paços de Ferreira.

Neither a transfer to Benfica nor a loan spell to Córdoba worked out but Rayo represent a solid platform for the forward to rebuild his career. He needs look no further than Kakuta, whose career was also drifting before he pitched up in Madrid.

Kakuta looks to have regained his love for the game at Rayo, only missing three games last season, and now finds himself at Europa League champions Sevilla after being released by Chelsea.

You would have to be a brave man to bet against Rayo avoiding relegation again next season, which is a credit to Jémez, his coaches and his scouting team. Few other clubs in Europe operate in the loan and free transfer market as shrewdly as Rayo do and, due to possession-based football Jémez looks to promote, the club is fast becoming an attractive place to play football.

By James Robinson. Follow @JvmesJournalist