You have to think of this from the product owner's stand point. He or she may get a dozen or so emails everyday asking for a review copy. How many of these requests are real vs freebie seekers?

Would you go to clickbank and email product owners about getting a review copy?

If you really want to promote it then the best way is to make some calls to the owner, or be able to give a proven track record of sales.

Thanks
Charles