Shoplifting an Item That I Thought Was a Sample

My question involves criminal law for the state of: Florida

I went to Macy's and picked up what looked to me like a sample packet: it was like a pouch (think of the little "folders" that sample perfume vials come in) and didn't have a barcode on the back or front. Then I went to another counter where I handed the person the stuff I wanted to buy. He offered to rung up the "sample" but also thought it was a sample. I paid with my debit card. I put the items into my transparent purse and went around the store again to look at more stuff. I had another look at the "sample" and a nearby salesgirl told me that it was $15! I thought she might have been joking and exited the store. The alarms didn't go off, and no LP personnel stopped me.

I feel terrible, especially since Macy's is near my house and I paid with my debit card meaning that they have my info on hand. What should I do to minimize trouble?

Either you thought the sales girl was lying or you didn't ? If you thought she was lying what changed your mind. If you believed her, why did you leave the store without paying for the item ? Why didn't you just leave the item in the store ? Nothing is that important.

I thought she was joking because $15 would be a ridiculous amount to pay for a sample-sized packet. When I got home I looked it up and saw she was being truthful.

You were buying cosmetics and you were surprised that the prices seemed ridiculous? Was this the first time you ever bought cosmetics?

Anyway, you say you got away with the goods, so if you're not happy with the fact that keeping it is an act of theft you can take it back or pay for it.