Checking Apple's store, I can't find a cheaper configuration than $5100 for the M5 + 128GiB version.

Here in Europe, including 21% VAT, that's €6.124,00 ($7.094,35 equivalent).

Because of pricing strategies and such, the 128GiB version comes with a 2TiB SSD at minimum, and also requires the M5 Max (not Pro) at its highest configuration.

Not sure if this is new, but it should be noted that these laptops don't come with a charger any more.