That's called, "Release on own recognizance" or referred to as ROR. That's where, technically, you're not posting any bail, but technically under the law it's deemed to be bail. It's ROR.
Yes! In California, bonds can be posted twenty-four hours a day, seven days per week. But whether you can bail someone out of jail at any time depends on their situation. When someone is arrested, they have a first appearance soon after.
No - if you signed the bond it doesn't matter whether you have a job or not - or whether the bondsman asked you if you did. You are liable as surety on the bond - having a job or not has nothing to do with your liability. Sorry.
The defendant can post their own bail or ask a family member or friend to post it. If the defendant uses a bond company, the company may require the defendant to have a co-signer (someone who will help the company find the defendant should they fail to appear).
For less severe offenses, such as misdemeanors, bail may be more readily granted. In contrast, for violent or serious felonies, it may be more challenging to secure release.
In some jurisdictions, the court may also allow you to post a property bond, which will use property that you own as collateral for your conditional release. Unfortunately, though, if your bail amount is high, you may not have the resources to post bail with the court on your own.