For example, from Transfermarkt:
United:
Maguire for $87m but MV was $50m
AWB for $55m but MV was $35m
Lukaku for $85m but MV was $50m
Lindelof for $35 but MV was $22m
Liverpool:
Alisson for $62.5m but MV was $60m
Keita for $60m but MV was $65m
Fabinho for $45m which is same as MV
Salah for $42m but MV is $35m
Many more examples for other clubs too
Market Value when they were signed, or Market Value as of right now? Really important distinction...
MV when signed, transfermarkt has the MV on transfer date