I got ripped off for $100. I was on Haight street in San Francisco and a guy offered me acid. I said no thanks, but I am looking for some hash. He said no problem, led me around the block and then said he needed the money first and he'd be right back with the hash. He pressed a baggie full of "acid" into my hand as collateral. Twenty minutes later, he hadn't returned and I inspected the baggie and it was full of little pieces of (not blotter) paper.
Nah it was pretty obvious to me. Dude was hustling. I ended up meeting another kid down there who ran around all night selling "haighths" of weed I had brought from Humboldt, until I had made my money back.