What's the worst scam you've fallen for (or gotten close to falling for)?

When I was about 16 I was walking past a nightclub as some guys were packing up a van outside. One of them called out to me and started telling me a story about how they were fitting out the club with a new sound system and had some surplus speakers. They asked if I wanted to take them off their hands. Really, I wanted to go and research them first, but this was in the olden days before the entire internet was in your pocket. They showed me the brochure and manual, I gave them £200 cash, and they drove me home in the van with the speakers. On the journey I started to get suspicious and got them to drop me a few roads over from my actual house. Lugged the speakers home by hand, started researching them and found it was a common scam. The units themselves were totally fake and from what others had said were a fire hazard. Police weren't interested as I had given the money freely. I had a buddy take them to the dump in his van. I spent quite a while researching who was behind it and ended up with the details of the "company" manufacturing the units in a workshop in London. I then spent a few weeks having fun prank calling them with various soundboards (Arnie was the best!). I made my peace with the whole scenario by framing it as an overpriced, but entertaining subscription to a guilt-free prank call experience.