I do not know PA labor law. However, in CA you can be terminated for any reason or no reason unless you have a contract or a union agreement. Messing up two quotes sounds like a valid reason. The overcharging is not a reason unless you threatened to report them to the authorities and they fired you for threatening to be a whistleblower. Sorry about your job loss. You might want to consult a PA attorney to see if you were wrongfully terminated under PA law.
The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change.
Pennsylvania is an at-will state in which you can be terminated for a good reason, bad reason, or no reason at all. The only exceptions are for violations of public policy, which has been defined by the courts as enactments by the Pennsylvania legislature or U.S. Congress.
There is no private whistleblower law in Pennsylvania, so if you have objections to the manner in which your private former employer did business, you need to find another employer.
You should be eligible for unemployment compensation, however, unless the employer can prove that your termination was for "willful misconduct."