The negotiation phase of a transfer in world football can be tense, fraught and drawn out. Very rarely is a deal struck that leaves both sides feeling as if they got the upper hand.
Manchester United have made plenty of bargains over the past 10 years, luring players like Nemanja Vidic, Edwin van der Sar and Javier Hernandez to Old Trafford for relatively tiny sums.
Saying this, the club has also overpaid in the transfer market. The likes of Bebe, Dimitar Berbatov and Dong Fangzhuo come to mind in this respect.
Estimating a footballer's worth can be a tricky task—one usually based on age, contract length and the financial position of his club as much as on pure ability.
The Red Devils are likely to make several signings this summer, with Sir Alex Ferguson pushing for European glory in his final few seasons at the club.
Here is a look at United's top six transfer targets, with a bit of financial guess work used to determine how much they should pay for each.
PSV's Kevin Strootman has been tipped by many to be Manchester United's marquee signing of the summer.
The box-to-box midfielder possesses all the qualities needed to succeed in the Premier League—he is physical, provides excellent defensive cover on the back foot and is a surprisingly creative force going forward.
Speaking last Wednesday on the link with a move to Old Trafford, the Dutchman said, "Every transfer window there are clubs that are interested, but [a move] should appeal to me" (via Goal.com).
Despite being a well-known talent, Strootman's potential transfer shouldn't be expected to cost the Red Devils more than £20 million.
Ideal Sum: £16 million
Maximum Sum: £22 million
Though he doesn't play in a position of priority for Manchester United, Robert Lewandowski is a known target for the Red Devils.
A report in French newspaper Le Figaro claimed last week that "Lewandowski has been high on United's wanted list for a while" and that a deal could be imminent (h/t The Express).
The Poland international has been in terrific form for Borussia Dortmund this term, striking 26 goals in all competitions, and has been a key reason for the Bundesliga club's recent rise to prominence.
In terms of pricing, Lewandowski's exit from Dortmund is widely expected due to his rapidly expiring contract, so the ideal sum would be the right side of £20 million.
However, the Daily Mail claimed earlier this month that a bid closer to £26 million might be needed to secure his services.
Ideal Sum: £17 million
Maximum Sum: £24 million
We come to the big one—the potential transfer that has Manchester United fans salivating at its mere suggestion.
That transfer cost Los Blancos £80 million—a record sum that remains the largest ever paid for a footballer.
With Ronaldo's contract two years away from expiring and him unlikely to re-sign, it is highly improbable that Real would recoup what they paid.
If the Portuguese superstar were to return to Old Trafford in the near future, his price would be steep. But if it's a return to Old Trafford he wants, United could get him for as little as £50 million.
Ideal Sum: £50 million
Maximum Sum: £65 million
Juventus' Arturo Vidal has been one of the true breakout stars of the 2012/13 season and can certainly be considered the best player of his type in the world today.
Only this past week did I write an article extolling his virtues and describing him as Manchester United's ideal signing of the summer.
Earlier this season, The Mirror claimed that "United are understood to be impressed by the dynamic midfielder as they continue to search for a central player in the Roy Keane mould. The club are reported to have contacted Juventus about Vidal's availability."
With Juventus seemingly not interested in selling and Vidal content with his current surroundings, it would likely take a massive offer on United's part to seal a transfer.
Sir Alex would love to get him for £27 million, even if his worth is closer to £37 million.
Ideal Sum: £27 million
Maximum Sum: £36 million
With Patrice Evra having a renaissance season for the Red Devils, talk of a move for Everton left-back Leighton Baines has cooled.
This despite the England international gradually developing into the best player in his position in the Premier League.
In December, a report in the Daily Mail claimed that "talks between United and Everton over the protracted transfer have reopened and Old Trafford chiefs feel the Merseysiders will now sell the England star for £15 million."
With Baines turning 29 later this year and Everton known as a club that struggles financially, £15 million feels like a slightly disproportionate sum all things considered.
David Moyes and Bill Kenwright always drive a hard bargain, though, and Sir Alex would be lucky to get his man for less than £10 million.
Ideal Sum: £8 million
Maximum Sum: £13 million
If there is one player repeatedly linked with a move to Old Trafford who fascinates the most, it may just be James Rodriguez.
For those who have seen him in action for Porto this season, his talent and potential seem off the charts.
A report in the Daily Mail on Friday claimed that the Colombian attacking midfielder is "is back at the top of Manchester United's wanted list."
With Rodriguez's contract containing a £36 million release clause, the Red Devils would have to pay a large sum to land him, even if either Anderson or Nani were included as makeweights in negotiations.
Such a sum is worthy, though, for a player deemed the next Carlos Valderrama in his home country (via UEFA.com).
Ideal Sum: £26 million
Maximum Sum: £36 million
How much should United pay for their top transfer targets?