Many look for a deal on a 1 day/2 park pass. It goes for about $70 at the gate, not even on the menu, not the best idea.
There is a season pass for $99 with some blackout dates, this may work depending on when you come. For someone who is coming down 1 time, and only wants to visit for 1 day, you'll end up paying full price at the gate for 1 park.
They want you staying for more than a day, and if you notice, the tickets are not good after you leave. In the past, they didn't expire, now they do. It's all marketing, they know what people want, but steer you to more days.
In your case, I'd say to visit IOA, even if the kid doesn't want to ride the coasters. Spiderman is worth it. Who knows, he may get up some courage and go on Hulk.
In the grand scheme of things, 10% off a $50 ticket is only $5. There are other ways to save that money. It's just that everyone who visits, expects to get a coupon because all the parks up north have them. In Florida, it's different because there are two parks and they want you staying longer.