When you get arrested and bail gets set the bail amount is determined by looking at the persons criminal history, how severe the crime was etc.
For example bail for something such as assault and battery would be less than bail for a murder.
With murder your bail would likely be around $500,000 to 1 million dollars.
The bail for the assault and battery may only be $500.00 or less.
Bail to get out of Jail is determined and set by the Judge and is based on factors like the severity of the alleged offense, the likelihood that the defendant will commit additional crimes after being released, and the chances that the defendant will flee the jurisdiction before trial.