Here is a question I recently received from a college classmate:
"My husband's cousin is having his bar mitzvah and we can't go. What is the going rate for $ as a gift. Also, would they have bar mitzvah cards at Target? Thanks for the info. Hope you're doing well!"
And my response:
"It's traditional to give a check in a denomination of $18 because the number symbolizes life. You can give $18 or $36 or whatever you feel is appropriate. If you want to give $25 instead that's totally OK too.
As for a card - some Targets will and some won't. I'm not sure where in the Phoenix area you live, but my guess is the closer you are to Phoenix or Scottsdale (higher Jewish population centers), the more likely it is you will find Jewish cards. My Target in suburban New Jersey event had Hanukkah pet items this year so anything is possible.
Mazal tov (congratulations) and enjoy the bar mitzvah!"