In a world where the all-time record transfer fee has almost eclipsed the £100million mark, it's becoming increasingly difficult to decide what a player is actually worth.
Is it simply a case of supply and demand - and if so, what affects the latter? Recent form, availability, experience and proven ability all come into the equation.
Trying to find some logic to the madness are Transfermarkt.com, who've made it their mission to detail the current market value of individual players by considering prior transfer fees, contract length, weekly wages and other underlying factors.
Tottenham Hotspur are one of the Premier League's better clubs when it comes to protecting market value. This season alone, they've extended the contracts of Christian Eriksen, Eric Dier, Dele Alli and Danny Rose.
With that in mind, we at Football FanCast have been taking a look at current market values within their first-team squad. The Top Ten certainly makes interesting reading...
10. Moussa Sissoko - £15.3m
Did Tottenham overpay for Moussa Sissoko during the summer? Transfermarkt seem to think so, valuing the France international at just £15.3million - almost half the £29.75million fee Spurs shelled out to Newcastle United.
9. Mousa Dembele - £15.3m
Many view Mousa Dembele as Spurs' most influential midfielder but he's only their ninth most valuable player according to Transfermarkt at £15.3million. The Lilywhites paid Fulham £16.15million for his services four years ago.
8. Dele Alli - £17m
Dele Alli's market value has soared since Spurs snapped him up from MK Dons for a meagre £5.6million in January 2015. He's now worth around triple that sum - although we at Football FanCast reckon Spurs could command upwards of £50million for the England international.
7. Jan Vertonghen - £19.55m
Despite a contentious contract situation, Spurs centre-back Jan Vertonghen is still valued at £19.55million by Transfermarkt - a noteworthy increase on the £10.63million fee the north Londoners splashed out on him in summer 2012.
6. Hugo Lloris - £20.4m
Hugo Lloris is one of the top goalkeepers in the Premier League and that's evident enough through his £20.4million market value. It's rather staggering to think Spurs coughed up around half that sum, £10.63million, to sign the France No.1 from Lyon.
5. Heung-Min Son - £21.25m
Despite netting four Premier League goals already this season, Heung-Min Son's current market value, £21.25million, is less than the £25.5million fee he cost Spurs in summer 2015. That's likely due to the fact the South Korea international is yet to renew the contract he signed a year ago.
4. Erik Lamela - £22.1m
Under contract until 2020, Spurs have done well to protect their £25.5million investment in Erik Lamela. The Argentine international's market value is currently just £3.5million less and after a few years in the wilderness, Mauricio Pochettino appears to be getting the best out of him on the pitch.
3. Toby Alderweireld - £22.95m
Toby Alderweireld has rapidly established himself as one of the best centre-backs in the Premier League since signing for Spurs in summer 2015. Transfermarkt rate him at £22.95million - a significant increase on the relatively modest £13.6million fee Daniel Levy paid Atletico Madrid.
2. Christian Eriksen - £26.35m
Christian Eriksen has proved an absolute gem since arriving at White Hart Lane from Ajax in an £11.48million transfer deal. He's now Spurs' second most valuable player at £26.35million.
1. Harry Kane - £34m
Who else but Harry Kane? Spurs' superstar striker is their most valuable player by a country mile and Transfermarkt reckon a potential suitor will have to pay at least £34million to prise him from the club's clutches. Much like Dele Alli, however, we think Tottenham are in a position to demand a phenomenal fee for the England frontman.