Torrance-based eCOST.com, an online retailer of discount electronics and other products, has completed its merger with PFSweb. The two companies said that both set of shareholders approved the merger at a special meeting last week, in a one for one stock swap. The companies said that expect a $4 to $5M annual cost savings from the merger. PFSweb is a provider of third party logistics, call center support, and outsource e-commerce services.