I don’t know what you’d consider cheap, but my ring was under $1500 and I think that’s on the low side. According to a study, that price is right in the sweet spot though. NBC News reports that men who spent $2,000-$4,000 on an engagement ring had a higher rate of divorce (of about 1.3 times) than men who spent between $500 and $2,000.
However, if you don’t spend enough that’s an issue too. A higher divorce rate was found in women whose ring was less than $500. Now, these prices and rates just correlate, it’s not causation. So don’t fret if you’re happy and your ring was outside of that sweet spot.
The article brings up a couple other good points. If you can’t afford an expensive ring but you opt for one anyway, that could put financial strain on you. That strain could lead to arguments. Also, the bigger the wedding, the more opportunities for disagreements.
So, you know, just do what works for you and makes you happy.