There’s a big difference between the behavior of a devoted subscriber and someone who casually picks up a magazine at a newsstand. The subscriber typically looks forward to and reads each issue. The newsstand buyer is drawn in by whatever is on the cover; it’s an impulse purchase. Subscribers tend to be avid hobbyists. Newsstand buyers are more likely to be aspiring hobbyists.
In addition, there’s the question of how many people you reach with your advertising dollars. With a subscription-based publication, you reach a predetermined circulation base. With newsstand sales, you’re usually told what the distribution is – that is, how many copies are printed and shipped out for sale. What magazine reps rarely volunteer is what the sell-through rate – how many magazines are actually bought. It’s common for the sell-through to be about half the distribution, so what seemed like a bargain at first may not be.
These are of course broad generalities, not hard-and-fast rules. I’ve had occasions where SIPs have done extremely well for my clients. But before you buy, consider who exactly the magazine is likely to attract, and dig a little deeper into the distribution numbers.