The perfect modern consumer/sucker...

My car needed another key. The stealership quoted me >$400 for it. I took it as a personal insult and did the research and ordered an OBD device and also discovered you can order replacement keys on aliexpress, and they'll even cut them for you with a good picture of your existing key. It was actually a fun project and very satisfying when I was able to successfully program and link the RFID chip to the ECU to start the engine.

May not be feasible with more locked-down modern cars which I wouldn't touch with a ten-foot pole, but I was able to fix it for about $150, not including my time of course. But I have the OBD device to use next time now as well.