Try before you buy

The marketing strategy of sampling or "Try before you buy" is still alive and well it seems.
For example: iTunes Store lets you hear samples of any song before purchasing, Baker's Delight offer you a taste of their daily bread or scones special at the counter. In my own coaching practice I offer all new potential clients a free coaching session so they can see if my coaching style is a good fit for their style and to see if coaching is for them.
I find this is the best way to add value to a potential client and allow them to get a real life experience of the benefits of coaching.
Sean D'Souza, a marketing writer described revealing a lot of your best material as "The Bikini Concept" because a little taste makes people interested in finding out the rest. Here's a link to his article http://spidersecret.com/so-what-if-you-give-most-of-it-away-the-bikini-concept/
So have any of you ever offered a trial product, sampling of information or services as part of your marketing strategy?
Cheers
Heidi Alexandra Pollard