That is according to Arsenal legend Ray Parlour, who believes the Eagles defender is an “excellent player” but not yet worthy of such a price tag.
Manchester United are on the hunt for a right-back to succeed Antonio Valencia, who will leave when his contract expires at the end of the month.
Ole Gunnar Solskjaer has made Wan-Bissaka his top target following the Crystal Palace ace’s impressive campaign.
An opening offer worth £40m has been rejected, with Selhurst Park chiefs holding out for as much as £65m.
But Parlour says it would be “absolute madness” for Old Trafford bosses to meet Crystal Palace’s valuation of Wan-Bissaka.
“I really like him, I think he’s an excellent player and I’ve seen him on quite a few occasions,” Parlour told talkSPORT.
“His defending is very good and he gets forward. But for £65m? It’s crazy.
“I mean, look at those Ajax youngsters.
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“They’re only young and they’ve not really done anything yet.
“They’ve really shown that they can play in an Ajax shirt and have done really well in the Champions League but they’re going for £70m-£80m as well.”
Meanwhile, Liverpool legend Steve Nicol believes Wan-Bissaka is a better option at right-back than Manchester City and England rival Kyle Walker.
“Going forward he’s good, he’s young, he’s 21, he’s got loads to learn with the ball at his feet,” Nicol said of Wan-Bissaka.
“But what I like about him as much as anything, the guy wants to defend.
“There’s not many full-backs these days that want to defend.
“It matters to him. That’s the sign of a good defender.
“When it actually matters that you’re even getting beat or you can’t stop the cross, it matters to this guy.
“As far as the price is concerned, if Kyle Walker goes for £50m, Wan-Bissaka in my opinion is a better footballer than Kyle Walker.
“Right now, is he a better defender? It’s eeksie-peeksie.
“But I’ll tell you what, he’s only 21 and he’s definitely going to get better.
“So if Kyle Walker’s £50m, then Wan-Bissaka is definitely £50m-plus.”