Graduate School -- Calculating a Reality Check

I've been doing a lot of daydreaming about graduate school as of late. If I can manage to get past the GMATs and possibly retake the GREs for a better score, there's still one more overwhelming knot I must tackle: reward vs. cost of a graduate degree.

Today, I started a spreadsheet to attempt understanding just how much money over time each of my top-choice programs would cost me. I tried my best to fairly estimate how much it would cost for a year including tuition, room, board and other necessary costs. My top-choice schools range from $30k a year to $80k a year. Most programs are 2 years, some are 3. Some are MBA programs, others are in design research. My top choice is in both, and happens to cost the most when lost salary is added in (it's a 3 year program.)

Based on my current income, I feel it is safe to say that I could make $100k average per year during the time I would be in graduate school. So to understand the total cost of school, I've added that yearly lost income. Granted, I could freelance and consult on the side during school or obtain scholarships and other work situations, but at this time I'm looking at the cost of graduate school w/ no work vs. working full time. And I can't handle the results of my calculations.

My top choice school, which would grant me an MBA and a Design masters degree, will cost approx $500k over 3 years. (WHAT? A HALF MILLION DOLLARS?) It's $160k total, give or take, without the income loss factored in. Quite frankly if I continue on the professional track I'm on now I can probably match any income bump I'd get from having an advanced degree.

Now, the thing is, I'm not going for my masters degree for a raise. I'm going because I want to give myself a fighting change to lead product management for an innovative company. That leads me to wondering, however, if I'd be better off investing that $500k in starting a company instead of going to grad school.

Even the in-state program that I'm interested in will cost me $260k over a period of 2 years including lost income. How can I justify this kind of spending?

This all comes at a time when my networth is eeking closer and closer to $100k. At the moment, that seems like A LOT of money. But when I look at the cost of these graduate degrees (and the cost of life in general), it seems like pocket change.

Looking ahead to the future I know I won't have the luxury to save as much as I do now. I'd like to start a family when I'm in my early 30s. My boyfriend is also planning on going to school so will have loans as well. Once I go to graduate school my value will be entirely in the amount of time I work in life. These days I feel like it's a waste of time to do anything other than work... all my freelance projects earn me additional income - why spend time outside at a park when I can be earning valuable cash to invest when the market is down and I'm still young?

Not that I'm complaining... life is going really well, esp given the current economic circumstances. I'm just trying to figure out how to justify graduate school to myself when on paper (eh, Google docs spreadsheet) it just doesn't make fiscal sense. Then there's this whole "having to get in" issue as well.