On a niche forum, I offered members $10 off on a $250 widget. One member complained that the $10 was just 4%. I replied that I could raise my price to $300 and offer $60 off, which would be 20%, and asked the member if he'd be happier with that. He hasn't replied. ;)
However, another forum member PM'd me and said that his family's B&M business does that very thing every summer. They'll raise their "regular" price and then promote a X% off sale. He said it works.
Has anyone here tried that?