The calculator was hiding in the back of the store, tucked away from the inexpensive items put on display up front to lure shoppers into a sense of false security.

By the time my wife, my kids and I got around to shopping for school supplies, the front shelves at Wal-Mart were pretty well picked over. We scrounged for a while, not realizing that there was a bigger selection midway back in this aircraft carrier-sized store.

Once we got there, though, we found the single most expensive school supply we've bought so far in our quest to raise our two kids: A T1-83 graphing calculator.

This calculator wasn't one of those...