Paul Pogba became the world's most expensive player when he rejoined Manchester United last summer for £89m, while the big teams in the Premier League are now accustomed to spending more than £50m to land their top targets.
The transfer frenzy has also filtered down into the Championship, with Norwich's Robbie Brady currently the subject of a bidding war that could see him go for more than £13m.
"I don't think these figures should be any surprise to anyone now," Neil told reporters at his weekly press conference. "The last two windows have been remarkable at times in terms of the valuation some players go for.
"It is like anything, the valuation is only there because people have shown they are prepared to pay it. They are willing to pay ludicrous money for certain players. Now if you are fortunate enough to have one of those it can be good, because you can accumulate a lot of money by moving one player on. The downside is if you are looking to buy one of those.
"The key for every club is you try to sell at the highest price possible, try and buy at the lowest but everyone is trying to do that. Generally the players who are coveted and are watched are being so by many clubs."
Neil's side - currently ninth in the Championship - have yet to dip into the transfer market this month.