Many companies will not give you a free sample of their product to try before you decide to buy it, and many of them are reputable. Protein factory, who I work for, offers money back as does EliteFitness, as far as I understand their policies. There is no risk to the consumer in this way, and they're not giving out samples to people who will never make a purchase.
As far as the original question, Havoc (Epistane products) seem to be under fire right now as to their legitimacy, and I don't feel Xfactor is really worthwhile.