I have a few. As 19 year old students my mate and I saw a sale in Jigsaw and we naively thought we could afford it. I saw this lovely, butter-soft suede mini skirt in a lovely, deep, chocolate brown. I didn't actually feel confident wearing it, but it was £15 and my mate was egging me on so I went to the till. Yes, it was £215 and I stupidly paid thinking I'd go back and return it tomorrow. No returns, they said. I barely wore it, too.
DP has a worse one - we were moving house and she'd done bugger all of the work house hunting so I insisted she get her finger out and organise the removal van. He turned up, super-friendly, slightly weird vibe, and gave us a price. I told DP he seemed a bit off and she insisted he was from a reputable company and it was fine.
He turned up on the day, loaded all our stuff, drove off with DP in the passenger seat. Two hours in he hit a traffic jam and declared it was silly to carry on and he'd drive back home and do it another day. Which he did. The next day he came back, picked up DP, and this time they got all the way there. At which point, standing outside our very isolated new house where we didn't know anyone, he demanded she pay twice the agreed price in cash to cover the 'double journey'.
She paid.
Then she googled him and found he wasn't a reputable company, he was a scammer who'd ripped off the logo of that company.
Oh, the joy.