Not to get all cranky and snotty here but...
These days I get alot of e-mails asking me to review products. I put alot of thought and energy into my reviews.
When sending out product samples don't skimp. Give me at least 5-7 servings/portions/usages. If not, I can't review your product properly. (And I will mention in the review that you were chinzy and I was unable to arrive at a firm conclusion.)
Same goes for sending me old product or damaged products. It will be mentioned.
If you are generous with samples, I can "share the wealth" and get other people's reactions as well.
Also, if you send me an e-mail about how you'd like me to write about your product but aren't willing to send me any samples? Dream on. I'm not going to buy a product I wouldn't normally buy and give you free publicity. Even if you give me a .50 cent coupon.