Depends on the state you are in. Depends on if you will be going after the skips or will you outsource that.
You will need a business license and I believe a permit. You will need some cash or a house to put up a couple of times as bail.
Lets say I get arrested and my bail is set at $1000. I dont have it so I come to you. Hey, bail me out I say. You say no problem. The fee is $100. I do not get that back. That is what it costs me for you to put up the $1000.
If I skip out you loose the $1000 until I do show up. If you hire a bounty hunter then expect to pay $250 to $500 in this case. (25 to 50%)
If you are not careful you can loose money. Most bail bondsmen I know get a boat load of info on the person and require them to check in often. I have been hired at an hourly rate to go see why this person isnt answering and to escort them to court.
If you want to do this you will need a PI on staff or on retainer.
My advice is to outsource the bounty hunting and PI work. Your insurance and liability will be lower and you wont be paying some cat just to sit there until you need him. Something goes down then you call your guy who is on standby and he goes to work charging you for what he does.
Hope that helps