All of this is to the best of my knowledge.
First of all you are not getting out of jail in Mississippi without a bail bondsman. Supposedly you are supposed to be able to cash bond out of jail for the full amount of the bail, but I have heard cases to the contrary were someone could not bond out without a bail bondsman. In short the laws are set up in MS to require a bondsman, so they will hunt you down on their dime after they have to pay the full forfeited bail amount.
As far as how much you will have to pay in cash to bond out, it will be typically 10% of the amount set for the bail. Thus, if bail is set at $10,000, you will have to pay $1,000 cash to bond out with the bail bondsman responsible for the full amount if you skip bail. As you might can expect, you don't get this money back. Once trial is complete what ever jurisdiction it is in might require a percentage as service for holding your money and the rest is forfeit to the bond agent. They have to make their money somehow!
I might be wrong, but I think the max amount that can required to bond out is 50% or $100 whichever is greater in MS.
Don't be surprised if bail on murder is set for $50,000 or more, much more, in MS. That is going by memory of news announcements where they announced bail being set.
All this doesn't even touch what a bail bondsman might require as collateral for signing the bond. You might be force to put you car, home, and business at risk as collateral depending on the bail amount. For that matter, a bondsman doesn't even have to bail you out if they don't want to do it.
This bags to question what is reasonable bail as envisioned in the 8th Amendment. Posting high bail for the accusation of murder could financially ruin a person and their family. Not to mention the legal expense and loss of income.