Cost of Cutting an Entry Door in Foundation Wall

[Robert Fisher]

Not sure if this is correct forum to post in so forgive me if I got it wrong.

I'm looking at a property that is begging to be a duplex but lacks a separate entry into the basement that already has a kitchen ready and waiting.  The best way to accomplish this would be to cut an entry door the concrete wall at the back of the house (as the basement currently lacks an entry point).

Has anybody done this before or have any experience with this?  Any help or advice is appreciated.

Thanks!