General Rule: You should spend at least 2 months salary on the engagement ring. If, for example, you are making $60,000 per year, you should spend $10,000 on the engagement ring.
Although there's no precise average amount spent on an engagement ring, most surveys of engagement ring buyers tend to produce an average in the $5,000 to $7,500+ range.
What kind of engagement ring can I get for $4000?
When you are shopping for a diamond engagement ring under $4000, search for a round diamond around 0.70 carat or a fancy shape diamond like a cushion cut, oval or radiant around 0.90 carat. For a round diamond, look for a near-colorless I color and eye-clean SI1 clarity.
Should the girl pick out the engagement ring?
There is no right or wrong answer. Simply, it's what feels right for both you and your significant other. What's most important is that both of you are on the same page and are happy and comfortable with whatever you chose to do, as this ring will symbolize the beginning or your new life together.