Give whatever you think you can afford, not what others think you should give!
People of means don't actually expect others to reciprocate...unless your last name is Corleone!
My wife and I came from families of varying income...most from my wife's side were of modest means. One of the guests gave us a plastic pasta strainer as a gift!
20 years later, we STILL have that plastic strainer and in fact, just used it last night!