AmzScope - Find profitable products for sale on Amazon in one click, relying on statistics instead of intuition
TrackIf - Alerts you if the price of your favorite products drop
Jungle Scout - Amazon product research made easy.
Coupofy - Coupofy is USAs number 1 trustworthy deals and coupons website.
AMZScout - AMZScout extension will help you make a decision about picking a niche based on the actual data, not intuition.
LoveSales - Find and save products you love, get alerted when they go on sale.