The perfect engagement ring should cost an equal amount to three months salary. This may sound like a bit much but that is the way that it has been for quite a while now. This comes from the diamond cartels that control the market and they know how to price a diamond. So in essence, if you make $1000 a month then the engagement ring that you select should cost around $3000. Of course you should always go with what you can afford and it is not a good idea to go into a marriage with a huge credit card bill from the purchase, so make a responsible decision but remember that this is a one time deal.
The perfect engagement ring should also reflect upon the person wearing it as well. If the person that you are purchasing it for prefers gold then you should not go with silver or platinum. You do not want something that will stand out or look bad on the persons finger to say the least. Also you want to make sure that the quality of the metal is good. There are some handsome looking rings floating around that are actually poorly made and the last thing that you want is some thing that will fall apart before the big day.
Be very aware of the cut and clarity of the stone. The size does not matter as much as the quality of the diamond in question. If you have a large stone that is extremely flawed then you have one of the worst bargains in the world. Make sure that you are getting only the best quality for the money that you are spending.