What are the approximate penalties for purchasing an unknown counterfeit product?

First, I'll bet she had to know it was counterfeit to break the law, which she didn't. As for penalties, they could be quite severe. A sentence depends on a lot of things like the exact charge(s), how cooperative the complainant(s) are, any injuries or property damage, the criminal history (including all arrests even if no convictions), behavior towards the arresting officer(s) and other factors.

Your question is not quite clear enough to give a detailed answer. This is because it will likely depend upon the type of counterfeit item and the value of it. Usually, counterfeit products, like handbags, wallets, etc. constitute a felony. However, once an arrest occurs, the best thing to do is hire a criminal defense lawyer right away and they will give you the rest of the information which you have asked about. It also depends upon where this matter is pending, in what county, since that can make a big difference in how severely the prosecutor handles the matter.