There were large national corporations which sold large and expensive items.  Then there were smaller venues.  It may seem foriegn to us today, but typewriters were the purview of the wealthy.  Writing impliments especially pens were a popular item to give as gifts.  This ad, from Gustave Fischer Company, suggests that if you "Like War News", then this is the pen for you.

The Chicago Plan

America was quick to find that business was loath to give up profits without any form of repayment.  Even the most patriotic business man had to watch the bottom line, or answer to their shareholders.  In response to this, the CPI adopted what was called the Chicago Plan.  Ad space was to be purchased by groups or individuals in print media, and tha was to be donated over to the government, under the auspices of the CPI, who would doll out the messages.  This was doubly effective when used in conjunction with the Liberty Loan Program.  Free money to advertise, free money coming in.  In payment for this, the business or organization would get credit for the expenditure by getting a mention at the bottom. 

Wildly successful, over 800 publishers themselves gave ad space of their own volition in addition to the corporate and private enterprises donating the space.  In 1918 alone, the Division of Advertising of the CPI estimated about $2.25 million dollars in donation went to the Chicago Plan, lone.  Had the war continued, there was every reason to believe that not only would this continue, but that it would accelerate.  The plan was so effective that it was used with billboards, posters. sandwich boards, and painted signs.

Because of this effectiveness, advertising a pro war message became trendy.  Recuitment drives almost always filled their quotas.  Print and film media touted constantly the greatness of America and how important it was to win the war against the evil Kaiser and his hun army, and industry took any aspect of the war to get involved.  American greeting cards came with messages like "deliver a victory against the Hun this Christmas", cereal makers such as Post touted that "Post Toasties Saves Wheat", and pen makers offered their products so that your boys can write home the news of the war.