I'm gonna do you a solid mate.
Go to your local pawn shop, buy two wedding bands, male size, at least a size 7. The average female has a size 6 or smaller finger (they has smaller hands, easy science).
Take those two bands, and have one polished if its relatively new, have it melted with flux if its not. Your average generic local blacksmith guild or club in your area can do this for you (Yes they exist, yes its awesome, and yes, we make all kinds of really awesome shit.)
Next go to a local computer, and look up online for local jewelrysmithing schools in your region, as well as art schools.
A school with a arts program (pottery and mechanical engineer is your magic button).
Put up an add in the local craiglist region that your looking for a custom clay mold, and that you'll pay a few hundred for it.
This will make it rain upon you like no other things in this world. College students at arts programs are heavily talented, and exceptionally poor, both because of constant need of study materials, and because of college. most liberal arts schools are in fact, more expensive than most other schools.
After you do this, the overall end product will be a custom negative mold of your ring, minus gem of course.
The site that I gave you sells damn near every gem on the planet, including ones you havent heard of. I studied gemology for over 3 years, trust me, I know.
This will allow for you to get both the ring forged, and the gem. All you need after that is to pay a small gem install fee, which your local jeweler can do, for pretty little actually.
Tadaaah! You have officially become a 2nd rate Zales on small scale.
You have a custom finished ring for very little, far less than the store will charge you. Your ring is a unique ring, one of a kind more specifically, and you save 10s of thousands.
Now go put that money in the bank you tigah! Save dat 512k college plan, and make dem babies!!!