Lots of sage advice. As expected of a forum with this many quality people (seriously, I've learned so much from this place alone). Also forgot to mention that the ad says the snake can go by itself for $75, which is still way too much but just throwing that out there.

I think, what I might do, is wait a couple weeks. Not only will I be in a better position by then (no immediate events, I'll have more funds, and as the fish I bought are the final batch for my setup, that will also be a more distant memory in my folks' minds), but the ball will also be in my court negotiation-wise should she still be listed. By then the owner will likely be desperate and possibly give her to me for free. I'm fully aware that potential vet bills and such will more than quadruple that "free" tag but, we'll see.

Keep in mind I'm not dead-set on this whole thing, I'm still thinking very carefully. It's more of a "Let's give this a good amount of time and see what conditions are like later" kind of scenario.