It provided a superb memorable deadline day's entertainment two years ago - but for fans of Liverpool and Chelsea the results since have been no laughing matter.
That money of course came because they sold Fernando Torres to Chelsea for £50 million, and the pressure was on to quell the fans wrath by buying a replacement.
Carroll was the flavour of the month at the time and Liverpool got suckered right in. He is currently on loan at West Ham on their treatment table having scored just once this season and is not expected to return until the end of the month. Right now it looks as though Liverpool would be fortunate to get £10 million for him.
While the football world is likely pretty united in agreement Carroll's transfer to Liverpool has been a monumental failure - Fernando Torres switch to Chelsea has been arguably more ruinous.
Torres' poor form since arriving at Stamford Bridge has overseen the sacking of three talented managers, and Chelsea fail to win a Premier League title since his arrival.
First to go was Carlo Ancelotti, the 2010 double winner, fired because he couldn't get Torres and Drogba firing in unison. His replacement Andre Villas-Boas tried but struggled to get Torres anywhere near his best, and also ended up getting the chop.
Roberto di Matteo may have won the Champions League, but this season became exasperated with Fernando Torres to the point he dropped him in their crunch game with Juventus. Chelsea lost and he was fired within hours.
Now up is Torres' former boss Rafa Benitez - If anyone can get the best out of him then its him - If he can't then its pretty certain the Spaniard is a lost cause.
If last night's performance against QPR was anything to go by, the future is bleak for Torres and Benitez. If Torres doesn't buck his ideas up then Rafa will likely be out on his ear come May, a fourth manager to take the brunt of his poor form.
And that is why Torres is a more costly failure than Carroll. Not only was he more expensive, but he arrived with a greater reputation and has been a larger disappointment.
Chelsea's staunch commitment to him through his inconsistency is hampering the club, and has seen three bosses sacked and you wouldn't bet against a fourth.
Perhaps it wouldn't be so bad if he didn't show the odd flash of his old self. At least Carroll has been consistently poor - Torres flattering to deceive just gets everybody's hopes up, and makes his inevitable return to his mediocre form even more difficult for fans to stomach.
Who has been the worst buy? Carroll or Torres?
image: © Nigel Wilson