Ebay and Bing Cashback Program

Pay Per Click, PPC or Sponsored Search Listings are all forms of paid search advertising. It allows you to purchase ads directly on search result pages and only pay when someone clicks on one of your listings.  
Sounds easy enough. The advertising budget has to be large enough for testing how many clicks to generate a sale until the right bid amount lines up with click conversion. Half the budget can easily be spent on finding what returns a profit.

Microsoft's Bing search engine is not as highly competitive on bidding for keywords as Google's search engine. Results are a little easier to get because bids are not so high, but the down side is getting enough volume to profit.

With the help of Bing cashback, eBay sought to separate itself from its competitors.  Rewarding consumers with a cashback rebate for purchases made online, advertisers experienced a substantial increase in ROI and the program became eBay’s top-performing campaign.

Microsoft's low-cost solutions across search and display range from $3,000 to $15,000 USD per month, you have a host of advertising options—from email solutions, online shopping datafeeds and banner advertisements to an integrated media solution utilizing both search and display.

All in all, a search engine marketing budget should be set at a point where an online business owner is not at risk.  I think paid search engine marketing done to strengthen an organic keyword campaign is the way to run a consistent web 2.0 marketing strategy.  Use a customized business blog to post relevant content and anchor important keyword phrases back to the most relevant page on the ecommerce site.  This puts the web site owner in control of running an inbound links campaign.