One reason we’re discussing this is per the prompting of Brave Supplicant smriti, who didn’t make it into a top-tier school and then decided that it was for the best, because those schools were financially out of reach. (You can read smriti’s words directly in the comments to this posting.)
It’s true that one component of the bschool decision-making process should be the financial factor. While some financial aid is available at some schools, it’s just not that prevalent and it’s pretty unusual to get a full ride to the best schools. Yes, all schools do offer some funds to some people, and once you’re outside the top 10 — in the middle-of-the-pack still-good-but-not-the-best range of schools — getting offers of a full ride become more common. The “best” schools don’t need to offer such incentives, and the much lower-ranked schools don’t have the funding available for them. Cornell has the Park Fellowship for example, and one Brave Supplicant we know was offered a full ride at Ross. We had a client accepted to HBS get a $20k grant but she was coming from the nonprofit space, and both HBS and the GSB are known to make more accommodations for those types. (ETA 6/14/12 HBS specifically only offers need based financial aid — they give money to admitted students based on your documented financial situation. And, they don’t run out of money; even if you apply in Rd 3, if you qualify for aid at Harvard, you’ll get it.)
If you’re an international candidate, you should look into what the student loan situation will be for you BEFORE you apply. Loans are readily available for American citizens. Foreign nationals can usually get a loan if they have a U.S. co-signer; some schools like HBS have secured partnerships with financial institutions that will loan to international students even without this. If you’re not a U.S. citizen or permanent resident, you may need to explore your options in getting funding from your home country, and you probably should do this in advance.
Anyone banking on getting some type of fellowship or assistance in financing should also apply in the earliest rounds, as more options are available then. Columbia for example has a fellowship deadline in early January; most people treat that as a “Round 2” deadline and they receive the bulk of their applications then. If you apply after that date, you are still considered for admission but you don’t get considered for any money. And if you’re applying to the Columbia J-Term: Sorry, but there’s no fellowship money available for you at all. So different schools do have different policies on this stuff.
As to whether the actual investment in the MBA is financially worth it? We still haven’t covered that part, have we?