If the amount was only $400. then it couid conceivably be a petty theft, unless the laws are that much different in FL vs. NY. I strongly suggest you speak to that "good lawyer" you wrote about and see what can be done for you. It may be better than you expect.
Some defendants initially want the easy way out: pay a fine or do some jail. But in my opinion, the best outcome is to have all record of this arrest sealed from public view. This is accomplished after the criminal case has been resolved; however, a defendant's eligibility to seal the record will depend on HOW this case is resolved. A defendant will qualify to seal his criminal record if the defendant has never been convicted of any crime. Therefore, to qualify for sealing, a defendant must do one of the following: (1) win the case at trial, (2) enter and complete Felony Pre-Trial Intervention, or (3) have the court's sentencing order state that the court is "withholding" of adjudication of guilt.
Taking a case to trial on these facts appears to be too risky in light of the other options available due to a lack of prior criminal history. The Pre-trial intervention Program (PTI) is basically felony probation for 18 months. The important aspects of PTI are that there is no entry of a guilty or no contest plea, and after successful completion, the prosecutor will dismiss the charges. If PTI is not available, a lawyer will request the judge to impose a probation sentence with an order "withholding" adjudication of guilt.
After PTI or Probation is completed, the defendant will be eligible to seal this criminal record from public view. This job market is too competitive to risk having a criminal record appear on an employers background check.
In Florida, theft of $300 or more is a grand theft of the third degree, meaning a third degree felony. So if a suspect allegedly switched a price tag so they could buy something without paying $400, and therefore obtain an extra $400 worth of property without permission, then that would be a felony level theft.
If there is no prior history with the defendant, it seems like there would be a good possibility the defendant could be offered pretrial diversion. Pretrial diversion, or "PTD," is a lot like probation except the defendant does not enter a plea of no contest or guilty. When PTD is successfully completed, the charges are dropped. It also depends on the facts. The state is less likely to offer PTD when the theft involves an employee stealing from an employer, but it does happen. Often, the victim must approve of PTD before the state offers it to a defendant.
Aside from PTD, the state may offer a plea offer in which the defendant could plea to a lesser included offense of petit theft, a misdemeanor.
Certainly there is no guarantee that anyone would be offered PTD, a misdemeanor plea offer, or anything. But with no history, it seems less likely that the state would be trying to "throw the book" at this person.
Another thing to consider is that in Florida, we utilize what are called "scoresheets." Scoresheets assign a numerical value for a particular crime as well as points for all prior crimes. It is unlawful for a person to be sentenced to prison on a non-violent third degree felony if there are less than 22 points on the scoresheet. A first time offender with grand theft third degree would score less than 22 points. This also suggests that since the state can't have the defendant sent to prison, they would be more inclined to try to resolve the case.
Alachua County's State Attorney's Office does engage in deferred prosecution or pretrial diversion, so there would be hope.
The defendant in this case should really consult with an attorney. An attorney can evaluate the facts of the case, determine the strengths and weaknesses of the case, and negotiate a resolution with the state. An attorney can work to get the charges reduced or dismissed, whether through a plea, PTD, or some other avenue.