Distinguish yourself from the rest of the pack. If you deliver your products in person or ship by mail, include something extraordinary in your box. Assuming you have a high enough profit margin, include a low cost item such as a bag of popcorn or some jelly beans. Make sure the "tag-along" package is well sealed. Include a note saying something like "thank you for your order". Assuming your client actually receives the free gift (and the mailroom or shipping department doesn't take it for themselves), you'll be remembered. Added advantage: your clients will now look forward to ordering from you so they can see what other "free goodies" you've included with their orders. Cost per order can be under $1.00.