Thank you for your follow up.
Unfortunately, the under the Maryland statute 3-1301 shoplifting is defined as following:
Shoplift" means any 1 or more of the following acts committed by a person without the consent of the merchant and with the purpose or intent of appropriating merchandise to that person's own use without payment, obtaining merchandise at less than its stated sales price, or otherwise depriving a merchant of all or any part of the value or use of merchandise:
(1) Removing any merchandise from its immediate place of display or from any other place on the premises of the mercantile establishment;
(2) Obtaining or attempting to obtain possession of any merchandise by charging that merchandise to another person without the authority of that person or by charging that merchandise to a fictitious person;
(3) Concealing any merchandise;
(4) Substituting, altering, removing, or disfiguring any label or price tag;
(5) Transferring any merchandise from a container in which that merchandise is displayed or packaged to any other container; or
(6) Disarming any alarm tag attached to any merchandise.
So as long as, the store employee has observed you switching price tags or has a video of you switching price tags, you can be charged with shoplifting.
Unfortunately, this is a criminal misdemeanor charge which is defined as follows:
Theft of property valued at less than $100
Misdemeanor under §7–104(g)(3)
Jail time up to 90 days; a fine up to $500; a requirement to provide the property or its value to the owner
I would strtongly urge you to consult and retain a local criminal defense attorney and this local attorney might be able to get you into deferred prosecution program, since you are a first time offender, which would allow you to pay a fine and receive a probation and avoid having any criminal conviction history, once you complete your sentence.
I wish you the best of luck!