What are the options of obtaining an MBA for people already working full time jobs?

My mother loves to keep learning. She already has a degree as an electrical engineer but she went into finance instead so she has wanted to get an MBA for a while now. It’s not really for job improvement as much as it is for personal satisfaction. The problem is that she already works full time and then also takes care of the home (cooking etc).

I was wondering if there’s any program where she could just study herself and then take an exam from some accredited place? She is a mom, and like most mom’s is unwilling to spend too much money on herself, which is why applying at some local college for night classes isn’t a good fit. She’s currently considering online programs, though they all seem to be quite expensive.

Since she has been working in the finance industry for a lot of years, and she is a smart cookie! I know she can get the degree, time and money are the issues. But I really want her to do this since she rarely does anything for herself. Any input on the subject is appreciated. Thanks =)