Many of the vinegars sold in the 10$ range will be Italian imports produced in the traditional method, but most will not be APIMO or APIRE certified. These certifications are given only to vinegars produced in the regions of Modena or Reggio, and no vinegar is given this certification before it is tasted and approved by a counsel of experts. If you buy an APIMO or APIRE certified vinegar you are buying a guarantee of quality – and probably paying for it too! [ this is usually marked on the Traditionale stuff -mc]
That's it. Buy a 10$ bottle of vinegar that has no artificial ingredients or sugar added and that is at least 3 years old and you will more than likely find a vinegar you are going to love!