No program charges less for part-time. Part-time students are presumably the ones with the highest means to pay for the program, either because their company contributes to tuition or the student has decent income from a finance-related job.
Being NYC-centric, I have only researched part-time programs in NYC. To my knowledge, Chicago may be the only other part-time program in the U.S. ranked top 15 aside from the list below.
Baruch MFE would be nearly the same, perhaps a few hundred more for part-time.
NYU MSMF costs approximately +$550/term. So if you take 6 semesters vs full-time 3 semesters, you'll end up paying $1500-2000 more.
Columbia MAFN part-time would cost anywhere from $7000 to $10,000 more. This is due to its residency tuition that severely disadvantages anyone taking 2 courses/semester.