Cash credits are given for the reviews written for the products or business listings, that have $ sign near the category. You will find the $ sign only near categories and not near products. Categories like Automobiles, Computers, Home Appliances, Electronics, etc have $ sign near them. Visit each and every category and the products listed in them and you could earn cash credits, if you write a review for the products. Make sure that the reviews you write are your own ones and not copied from other websites. Copied reviews will be deleted on approving and rating by the editors.
Keep a look out in the announcements tab where you will find contests posted from time to time. Currently there is no contest running. But we will have a new contest posted by next monday. You can participate in that and earn cash credits if you are chosen the winner.
Currently cash credits for product posting is discontinued. So if you wish to earn cash credits you have to write reviews.