I paid 2 week's salary just about exactly. I didn't do that on purpose, but that is how things worked out. She found the ring that she fell in love with, I picked the center diamond to match the budget that I wanted to spend. I did go 10% over my budget, but I think it was worth it.
Of course, with most things I purchase, people think I spent far above what I really spent. I drove a hard bargain at the cheapest wholeseller in the area. I got a quality diamond that looks bigger and sparklier than it really is (very well cut and polished, no color visible to the human eye, almost no inclusions). And I got a diamond with only one flaw that they filled then put under a prong. It was a bad flaw, but it was located in a small area on the very side. But once it was filled, no one can tell with the naked eye and the prong makes it impossible to see.