Print advertising is certainly worth it, but only if done correctly. I would not recommend running just one small ad in a monthly magazine one time. Small ads can work, but only as part of a "horizontal" ad campaign, i.e. one that extends over a long period of time. People need to see your ad multiple times before they will respond to it, especially since with a small ad you don't have a lot of space to tell your story.
If you're sticking with a small ad that can get buried in a magazine, I would recommend a minimum of 6 consecutive months, preferably a full year.
You could shorten that time frame with a larger ad, say a quarter page. Even at that, I would say three months would be the minimum.
If budget constraints don't permit these minimums, I wouldn't do it.
Don't fall into the trap of thinking, "Well, I'll just try it one month and see what happens." I guarantee that unless you're giving your stuff away for free, *nothing* will happen.
That leads to my next point...a big part of the response to any ad is the offer. Unless you're doing brand/image type advertising, a direct response type of ad requires a strong offer. "Unique T-Shirts available at
www..." will not incent people to respond. A good price, discount, limited time offer, etc. will result in response. You could feature one or two items, and price them lower for the ad, making sure to reflect the "regular" price in the ad: "Unique Military T-Shirt Now On Sale $16.99, Regularly $22.99" or something like that.
Even if the magazine is not a financially viable advertising medium for you, I'm sure there are other niche websites or publications out there. What about local military organizations' newsletters, either print or online?
Anyway, you're approach in evaluating whether to advertise or not in that particular magazine is spot on. Advertising is not an expense, but an investment. And with any investment, there's always a return. Hopefully a positive one.
Good luck!
- Bob