By Joseph Henchman of The Tax Foundation

Some 7,400 jurisdictions in the United States impose a sales tax, and most if not all of those taxes carve out exemptions and exceptions for politically-favored products. Keeping track of what's taxed and what's not in 7,400+ tax codes is a tough job, and if you mess up, you face fines and lawsuits.

For instance, the following items are among those exempt from Pennsylvania's sales tax: wrapping paper, toothbrushes, coal, coffins, horses (but only if shipped out-of-state or used for commercial racing), three kinds of trout (out of twenty), gum, tourist promotional materials, and toilet paper.

Yes, toilet paper—as the K-Mart in Monroeville, Pennsylvania recently learned. Local resident Mary Bach has filed a lawsuit demanding $100 in damages plus court costs because her $3.99 toilet paper purchase was incorrectly taxed (for 28 cents). Ms. Bach is no stranger to such complaints - she heads a consumer task force and led an outcry over grocery coupon rules. This lawsuit takes advantage of Pennsylvania's Unfair Trade Practices and Consumer Protection Law, which allows her, in this case, to seek damages 357 times her actual injury.

With so many exemptions and deductions in our tax code, the real news story should be when someone gets it right, not when they get it wrong. Businesses small and large can suffer as they try to keep up with the ever-changing mess.