Since people love free gifts, they're an inexpensive way any company can get people to remember their name and create goodwill. Smart businesses have used them since the very beginnings of commerce. Every single business needs printed items such as envelopes, business cards, and business forms. There's a lot of money to be made in advertising specialties and printed necessities. First there is volume.
Businesses order multiple products, by the hundreds and by the thousands.
Second is repeat business. Your customers give the pens away or use up the business cards, and then they call you and order more so you can make even more profit. Back in 1894, while Grover Cleveland was still in office, a small printing company opened in Cincinnati called The Cincinnati Printing and Paper Products Company. Every time you sell one of their products, you receive a percentage of the sale price as your commission. You just take the order.