Lower Costs Mean Higher Profits: Again, it's very simple. You need to focus on products or services that will be cost-effective. This means spending a reasonable amount to purchase (or manufacture) the product(s) and market/advertise them, leaving you with a decent profit. It's all about profit margin and punching numbers is crucial before you start any type of sales business. In the world of mail order, this also means factoring packaging and shipping costs into your equation. While you may love glass vases, if the cost of wrapping them for shipping is greatly diminishing your profit margin, then perhaps this isn't the mail order product for you.