Once, but I learned a valuable lesson on looking at prices, checking out my options and also buying on impulse. If I'm down I often go to ebay, and buy a little something to cheer myself up occasionally, and so if I do, I set a hard limit (this is back when I had money ha) and don't go over it, or else I know I'll be agitated with my purchase. I've never asked anyhow to cancel a transaction or anything if I couldn't afford it to my best recollection..I know I never have on ebay.