You could go out today and get a mortgage. The problem is, it would be on really horrendous terms. There's a big danger you wouldn't be able to keep up the payments and you'd lose the house.
The lower your score, the more you pay. See the FICO home page for examples of how the score corresponds to possible mortgage payments. Read a few threads on this forum and you'll get a better idea of how it all works. Good luck!
Bartender, bring another round of FICOtinis please!
9.4.2011: TU 805. EQ 815.