Honestly, I think charging an extra buck for the debut of an ongoing series is a short sighted, backward idea in an age where few books last two years, and fewer still surpass three, before being canceled or relaunched.
One would think that you would want to make issue #1 cheaper, to encourage people to pick it up and try it. That would rely on said issue providing a good enough story to entice people, though.
Instead, we have a philosophy of, "our books peter out by issue #18 anyways, so let's punish shops that hedge their bets by overordering on debut issues by making debut issues extra expensive to suck cash in the short term." It's akin to paying rent and utilities on your credit card. Eventually there will be a reaction, and it won't be good. If NEW MUTANTS #1 was, say, $2.50, would I be tempted to try it? Sure. For $4? Nope.
Right now both Marvel and DC are engaged in a game to try to draw more cash from less readers in a market they created where nothing but the "important" books can be counted on to sell decently, and that is about 30 titles combined from both companies. I genuinely fear what will happen when the market does what Quesada and DiDio have dared it to for years, and contracts dramatically.