If you get caught with a large pack coming via USPS you are going to be charged federally. It is a federal crime as it crosses both state and international borders as well as using the federal mail system. State police may deal with small packs deemed for personal use but the feds are going to step in on the big ones.

I found this information concerning Florida specially as I'm not familiar with their state law and this is what I pulled up on some attorneys website, so take it with a grain of salt.

The lowest-level felony charge regarding Xanax is possession. Possession, like trafficking, is based on weight. Additionally, the arresting officer may look to see how the substance is packaged. If it is individually-packaged, the officer may suspect you of attempting to sell Xanax. If the pills are in a bottle or in your pocket, it is likely personal use. Typically, the threshold for possession is 4 grams, or just a few pills.

If you are charged with sale or trafficking, your case is considerably more complex. Trafficking, which may range from 4 -14 grams, carries mandatory minimum prison sentences and mandatory fines. Mandatory sentences may range from 3 years at the bottom, to 25 years on the high end, depending on the weight of the drug allegedly in your possession.

Keep in mind that they are talking about the weight of the pills and binders combined

If you are charged with sale or trafficking, your case is considerably more complex. Trafficking, which may range from 4 -14 grams, carries mandatory minimum prison sentences and mandatory fines. Mandatory sentences may range from 3 years at the bottom, to 25 years on the high end, depending on the weight of the drug allegedly in your possession.