[Redliner]

I had my wife's ring custom made for her, and bought a Canadian (Polar Bear) diamond for it through the same store that made the ring. This was 11 years ago and I paid just under 5K. The ring is now appraised at $9600.

I had always been told that 2 months salary was a good guideline, and that's pretty much what it worked out to back then. Bottom line, though; spend what you can afford and shop around to get the nicest ring you can for your budget. Once you decide what your budget is, stick to it. If your fiancée is reasonable, she'll understand that starting out the marriage without a pile of bad debt is more important than wearing a 3 lb rock on her finger.