By itself it's a rather cryptic sentence. Of course that's not surprising in poetry and song lyrics. You have to look at the larger context of the song.
In this case, just go back one and forward one line: "Wake me up inside" and "Save me from the nothing I've become". So the singer is saying, "Wake me up, bid my blood to run." As Kiamlaluno says, "bid" here means to command or request. So the singer is saying, wake me up, and command my blood to run through my body. i.e. force me to be alive and conscious, and not to be a lifeless non-entity.
"Before I come undone": Again, as Kiamlaluno says, "undone" means "defeated" or "ruined". So the singer is begging someone to save her before she is defeated.
"To have a crush (on someone)" is a light-hearted and slightly juvenile way to express a strong affection for someone. It is mostly used to talk about young people's feelings, and does not normally describe adult emotions.
If applied to adults it can be an insult to imply the person is or acts immature. This depends greatly on context, however, as it can also be used as a compliment to imply someone is acting or looking youthful.
A "crush" doesn't have to be on a peer or someone of similar age. A young person can have a crush on an older (even a much older) celebrity or any other person. Also, a crush can often be one-sided, implying that the affection isn't returned by the other person (referred to as "unrequited love").
By using "crush" instead of some similar term, it implies that the feeling isn't serious and is likely to be temporary. Of course many young people will disagree with this, but that's the nature of youthful crushes. No one should be ashamed of a crush, but they might be deeply embarrassed if talked about in front of them.
How young is "young" can vary widely by who is talking. At my age, I might use "crush" for anyone under 30, but I'm a grumpy old curmudgeon.
Best Answer
I don't recall the context in the movie, but in general:
cheap: inexpensive or of poor quality.
slang: "cheap shot" is a verbal or physical attack that is very easy and considered cheating)
"Cheap" can refer to either the cost of a thing, or to describe a person that only likes cheap things.
"Don't _ on me": Don't do this around me or to me or in a way that affects me.
So the phrase "Don't get cheap on me." could mean one of: