After some trial-and-error (i.e. forgetting to cancel, and getting stuck paying; also, not always having a coupon or link handy), I've kinda gotten into a groove whereby I call them when I come into the US for Pesach and tell them "I heard there's an offer out there for 6 months for $25, with waived activation". If they say there's no offer for waived activation, I ask them to waive it anyway.
Those six months cover my Pesach trip to the US, as well as my summer trip to the US. Then, when I leave back to Israel for Elul, I cancel it. Next Pesach... lather, rinse, repeat.