"There's a criteria generally that Liverpool stick to, more or less, when they sign players, and he doesn't really fit in that in terms of age, potential profit and all those types of things," said Murphy.
Negotiations for Wan-Bissaka and other West Ham players are expected to accelerate as the summer transfer window opens.
"So it'd be a change of tact, but I think if you want value for money, you might just get him for a fee that you wouldn't be able to get (a top quality player)," said Murphy.
"You're going to have to pay for a top quality player on that right hand side.
You're going to have to pay £50m to £80m, aren't you," said Murphy.
"But with him going down to the Championship, I reckon you'd be looking at maybe £20m, £30m at most," said Murphy.
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"But let's say it was £20m because he's desperate to get out and then get him off the wage bill, then it's no risk," said Murphy.
