You're in business because your product or service delivers the benefits your customer wants, most often better than many of your competitors. 

You care about your clients -- they can tell by the way you attend to the details, respond timely to their requests, and genuinely connect with them.

Consider offering your prospects an opportunity to experience your business for free.  For your prospects, free is good, especially when they're trying out a product or service they're not quite sure about.  If they can "try out" the experience of owning what you offer, they'll understand the advantages of being your customer. And then, they'll be far more likely to actually make the purchase.

Consider your freebie a marketing investment.  It will be a limited experience of your product or service "in action".  Sure, since it is both valuable and at some small expense to you, you're risking that you'll get nothing in return.  But if you're truly confident in your quality and service, you can dramatically minimize your risk.

Thought I'd share a few good ones I've come across (and implemented many of myself):

• Gift certificates for your products or services.
• Free printed or electronic (CD, DVD) marketing materials.
• Donate money to worthy causes and offer their prospects and customers the opportunity to support the same.
• Free consultations that truly help their prospects.  Never make them seem like sales pitches.  Offer your prospect the opportunity to take the next step if they're interested.
• Give free seminars and workshops because you realize if they're truly value-adding, you will draw the right kind of people with whom you want to work.
• Offer invaluable information on your website.   Really awesome content will bring your customers and prospects back for more, thereby intensifying their connection with you.
• Freely offer examples of the quality service or product you offer:  testimonials, portfolio, samples, audio/video on your website, etc.  Someone else saying you're great is a hundred times more effective than blowing your own horn.

Think of your generosity as the equivalent of purchasing a new customer at a very low price.  My experience is that it surely beats mass print campaigns, radio advertising, billboards ... and almost anything else I can think of.   Exercise creativity.  You can display the highest form of creativity when you give for free what you ordinarily sell.

Your quality and service will prove more than anything you can ever say in a marketing piece. Your customers truly enjoy being your customers. Now, they know why you are so confident in your offering. Nothing can substitute for an actual ownership experience.