On the facts you state, your friend is possibly guilty, but you are not because he acted independently of you and you had no knowledge of what he was doing when he removed the tag. Your friend may or may not be guilty. Removing a security tag with intent to steal the item is a crime in some states, even if the person does not go through with it, but not in all states.
This does not mean that you cannot be found guilty. The manager is claiming that your friend handed the wallet off to you. On the facts you state, that did not happen. If it comes down to your word against hers, and that is the only evidence, then it could go either way at a trial and you would have a reasonable chance of success. A lot depends on what the video surveillance shows. If it backs up the manager, you would lose. If it does not back up the manager, you would probably win.
You do need a lawyer for this. If you cannot afford one, tell the judge that at the first appearance in the case and ask that a lawyer be appointed for you.
Another thing a lawyer may be able to help you with is to explore the possibility of whether a diversion or deferred sentencing program exists. If so, and you qualify for it, you may be able to avoid the risk of a trial. Diversion usually involves counseling and/or anti-shoplifting classes, program fees, and perhaps community service. If you complete the program, you can avoid a criminal record. It is not available everywhere, so you need a local lawyer for that.
It is not clear from your post whether you are being charged as a juvenile or an adult. In juvenile court the risk of a conviction in a case like this is higher if it goes to trial. Judges tend to side with the store and police. If you are charged as an adult, you have the right to a jury trial. A case like yours would play much better to a jury if you have to go to trial and cannot resolve it with a diversion program or other means.
You will probably receive a civil demand letter in the mail for several hundred dolars. That is separate from the criminal proceedings. Usually, I recommend that people pay it, but in your case, where innocence is a real issue you may want to resist it. Ask your lawyer about that.

