Business cards are the cheapest form of advertising (word of mouth is cheaper but not so reliable)... & they are to be considered "mini billboards".

The top 3 pieces of information that MUST be on all Business cards:
#1 "Who you are"  #2: "What you do"     #3: "How to get ahold of you"

If any of these are missing on your cards, you might as well be handing out blank cards.
Logo's.... clipart.... slogans are all additional fluff that does add to your cards.
Having a matching logo on all biz related items also get's "Company recognition" after a while.

So add one to EVERY package..... hand them out to anyone you meet. 
Buy them in lots of 1000 or more for the best prices!