The Sales Tax rate in Chicago is leaping up to a whopping 9% on Friday. The smarties will be making a mass exodus to the suburbs for big ticket items, where the difference in sales tax rates can be quite a chunk of change. I like to head up to Lake County to buy my fancy gadgets, where sales tax usually hovers around 6.5%. I bought my iPod in Vernon Hills last year, and saved $12.00 on taxes.