I never thought I’d be the type to obsess over spreadsheets. But then again, I never thought I’d find a way to score designer sneakers at nearly half the retail price. My name is Olivia, I’m a freelance graphic designer based in Portland, and my wardrobe is a chaotic mix of thrift store finds and high-end streetwear. I’m not exactly rolling in cash, but I have a serious weakness for Japanese denim and rare Nike collabs. Enter the mulebuy spreadsheet. It was a rainy Tuesday when my friend Jake, a vintage reseller, sent me a link. ‘This is life-changing,’ he said. And he wasn’t wrong. The mulebuy spreadsheet is basically…