I had to drop off my son at a Boy Scout camp in northern Minnesota yesterday, and it was an 8 hour drive round trip. So on Saturday I took my car to Jiffy Lube for a overdue oil change. In suggestive selling mode, the guy showed me my cabin intake filter, which was filthy and had a hole in it. He said that the dealership charges $120 to replace the part, but Jiffy Lube would do it for $40. Not thinking it through (i.e., no labor involved whatsoever), I said fine. He later came back and told me that they were out of stock on that filter but I could bring the car back.
Returning to critical thinking mode on the way home, I checked the Internet and found the filter for $5.95 (plus $5 shipping). The lesson learned is that I will never again pay to have a part replaced that I could replace myself without any problem (except an oil filter).