You've already gotten a lot of advice on one side of your problem, let me take a stab at the other side.
For the record, I design jewelry as a hobby, with designs ranging in value from $50 to $50K, materials from glass and semiprecious stones to diamonds over 3ct size and platinum.
1) The best deal in jewelry is estate jewelry. Often you can find very nice things that, were they made today, would cost 4-5x as much. A jeweler I work with routinely acquires findings (like rings without stones set in them) from estate sales- he can buy filigree ring findings and sell them for as little as $50. You can't buy a filigree ring from a major chain for that money, and you definitely can't get one made for that price- its lower than the cost of the gold in the ring.
2) The second best deal in jewelry is custom work from a reputable private jeweler- you know- the guys who have just a little store in the corner of a strip mall or some such. This is where I usually operate.
One of my Dad's assistants was getting married and her fiancee gave her a budget for her ring. She found one she liked at a major retailer. I referred her to one of the guys I usually work with, and he put her in a ring of the same style with a better mount (platinum instead of gold), and a diamond 2x the size and better quality than the one she saw in the store- for $500 less than the one in the store.
The chains have all that high overhead to deal with- rent in high-end malls is
buh-rutal! With a private jeweler, you can use the Johnny Cash "One Piece at a Time" method- you buy the diamond loose when you find a good one (or set- whatever); you buy your casting gold when the price is low. If you're not going the pure custom route, you can place your stone in a standard setting from one of the jeweler's catalogs or from his selection of estate findings.
How do you find a good private jeweler? Check with your BBB to find a good guy. Ask around your circle of friends. A good jeweler should take the time to educate you as to the cut, color, clarity and carats of the stones he's trying to sell you so you can find the right combo for you.
Depending upon your time frame, you should also check out the travelling Intergem show closest to your location (
http://www.intergem.com/).
Some of the guys I've met at the Intergem show can be found online. 2 gem suppliers/cutters with whom I've been dealing for
years are Bill Vance (at
http://vancegems.com/index.asp?bhcp=1) and John Rhoads (at
http://djraregems.com/index.html).
(As I recall, Treebore on these boards is a pro jeweler- you might want to track him down for advice.)
3) The third best deal in jewelry is returns to major retailers. Zales and others often have jewelry that someone has paid for in part, or returned for some reason and possibly abandoned. They can't sell the stuff as new, so they often sell it for the balance of what is owed, or at least at greatly reduced prices. I often shop these stores for deals.
A Reality Check on the practices of the diamond industry: while I abhor the blood diamonds and the monopoly control de Beers tries to exert (but which is crumbling, largely due to Russia), you can find similar histories behind almost any of the high-end (natural) stones. Ruby, Sapphire, Emerald, Tourmalines, Tanzanite, Gold-in-Quartz...all have a dark side. Heck, even the precious metals you set the stones in exact a cost in human lives.
Do I buy blood diamonds or other conflict stones? No, not if I can help it, nor does any reputable jeweler. But there is only so much a consumer who wishes to buy the real thing can do. Caveat Emptor.
but the rings you'd buy would be man made. )
