I have found some great things in charity shops over the years. Some of the best were:
two trenches - a longer taupe one (originally Debenhams) and a short black one (originally M&S - that one must have been with me for about 12 years now and is still a favourite) - both about £10-12 I think
three Boden cashmere cardigans in as new condition for £10 each
Very simple black faux wrap dress with the label missing, probably the most versatile dress I own, can't remember exact price but under £10
Long brown Fly boots for £5
Fitted black leather jacket - I think about £8
White Stuff khaki combats - maybe £12 (that was a more upmarket "boutique" charity shop)
when my kids were little - a pair of new looking Kickers boots (can't remember how much but certainly under £10) and an as new yellow Gap hoodie (about £5 I think)
I don't really consider it to be having a good eye though, just the luck of the draw - sometimes I don't find anything very nice in charity shops for anything up to a year. It doesn't stop me enjoying the chase though!