CHRISTMAS CERTIFICATES. A welcome gift to send along with your December letter would be aerating services gift certificates. These certificates would be worth $5 towards any service you perform. Since your starting price is usually $50 all you will be giving up is the $5 certificate amount so this is a perfect way of bringing in new customers around the holidays. The customer you sent the certificates to will also appreciate them because you may have solved one of the age old problems of "What do I give the milkman for Christmas." Many of your customers will use one of the certificates themselves and then pass the others out as presents. This will certainly start people talking about your company. Remember, the most effective method of advertising is word of mouth, so give them something to talk about!