I used to own my own business, KLW Enterprises. I designed and sold buttons and bumper stickers to the pagan and new age markets. Volume orders can make all the difference. The expenses above swamp the cost of the materials if each order is for only one or two items. If an order is for 100 identical items, the time spent per item is much less.
Advertising gets expensive fast.
I was much too optimistic about its effectiveness. Start with the circulation of the publication, estimate the percentage of people who will read the ad, the percentage of those who will want to order, and the percentage of those who will actually get around to it.