the teenager in question is my second cousin

Question for those more recently in the circuit than myself (for whom it's been 25 years): what is the going rate for a bar mitzvah gift of $? We will not be able to attend, which actually disappoints me probably more than anyone except the kid's father (my father's youngest cousin) and grandparents (his grandfather is my grandmother's baby brother). However, because the invitation was festooned with hoops and basketballs, I have also ordered a basketball yarmulke that I will send along in advance of the big day. In the event he doesn't already have one, I will win some number of cool cousin points - or provoke a fight over whether he is allowed to wear that yarmulke for his ceremony. Or both.