I recently helped a friend negotiate and complete a large purchase, in the neighborhood of $10k. However, about a week after we finalized the sale and right before delivery was supposed to take place, I got a call from our sales rep at the store. He said that they forgot to charge a special insurance fee that would add another $100 to the order. If we didn’t pay this fee, they said, the whole order would be voided.

My gripe here is not about the $100. At only 1% of the total purchase amount, it wouldn’t have affected our decision one way or another — if we knew about it before completing the purchase. Indeed, the problem is that nobody told us about the fee beforehand. This combination of bait-and-switch and nickel-and-diming became a big point of contention for me, especially since they decided to hold our order hostage over it. We ended up paying the fee, but my opinion of the retailer has dropped from “very good” to something in the “average to poor” neighborhood.

It seems like common sense, but no matter what you’re selling, you need to avoid surprising people late in the purchase process. Once you and the customer have agreed to what they’re buying, and especially after payment has been received, don’t tack on little fees and surcharges. If you forgot to charge for some small thing, suck it up, fix your process, and don’t make the customer suffer. In other words, get rid of the surprises that turn a great purchasing experience into a crappy one. Otherwise, you’ll see your repeat business drying up and new sales slowing down, all because you wanted to nickel-and-dime people with things that barely impact the bottom line.