I'm married, so my situation is a bit different because we have some income. That said, I'm still taking on close to $150k in debt. Plenty of folks go this route; just make sure you have your numbers dialed in. Here's a quick, dirty, and conservative calculation.
-1st year comp at MBB or 2nd tier consulting firm - $135k + $25k signing + $25k year end = $185k
-This is $85k more than your (or my) pre-MBA salary. Call it a $50k net increase.
-Factor in interest, modest raises, and modest bonuses and you're looking a loan payoff of 150 / 50+ = 2-3 years and a break even (opp cost) of 350 / 50+ = 5-7. Add a year if you let your quality of life improve significantly after school.
Some other things to consider when figuring out your cash flow (disclaimer: I'm not a tax advisory. Do your own research.):
-You can take either a $2,500 deduction for tuition and fees or a $2,000 Lifetime Learning Credit (generally a better deal). This applies to 3 tax years if you're a full-timer.
-You will likely have a significant internship salary in the range of $22-29k. You will also be in a fairly low tax bracket.
-You have some flexibility on when to take your full-time signing bonus. Most people opt to take if during fall of their 2Y. During that tax year, you'll likely only have an intern salary and your FT signing bonus, which helps with taxes.
-You can deduct up to $2,500/year in student loan interest. Coupled with a lower interest rate, this may make interest-only repayment while in school an attractive option.
-Deducting tuition as a business expense. Unless you have a great tax lawyer and are sponsored, don't even try it. You will get audited and the criteria for meeting this deduction are very stringent.
-If you are in a state (like Illinois) with tax-advantage 529 plans, don't forget to contribute. I contributed $20k to mine and 3 weeks later withdrew it. Results: $20k (max allowable) tax deduction @ 5% (IL flat rate) = $1,000 net benefit. This will apply during 3 tax years.
-This one doesn't really help your cash flow, but is a great hack for long-term income. Your years in school are likely your last years of IRA eligibility. You are also in a lower tax bracket than you have been or ever will be again. If you have an IRA/401k, seriously consider a Roth conversion. I'm planning to convert $50-60k over 2 years. Basically, I'll pay the 15% income tax now and the money will grow tax free. I won't have to pay 25-33% when i withdraw it in retirement.