eBay is jumping on the marketplace research bandwagon, and has announced a product that will be competitive with Sellathon, Terapeak, and other popular auction research tools.  "eBay Marketplace Research" will be available in 3 levels, the most comprehensive costing $24.99 a month.  There's also a $9.99 level that will give you the basics, and a $2.99 Fast Pass that will give you 2 days of access to the service.  Each level offers varying information as well as research results that go back in the eBay sales history for either 60 or 90 days.
 
Once you sign-up, you can cancel anytime; however, the fee is not pro-rated, so if you want to cancel, be sure to use the majority of the month.  You can check out the comparison of features here:  http://pages.ebay.com/marketplace_research/detailed-comparison.html and here's the official announcement:
 
 
Hi, this is John Bodine with Product Marketing. We know that sellers need information to run their businesses efficiently -- for instance, the price an item is likely to go for on eBay, or what types of items buyers are searching for. Likewise, buyers want to know the price they can expect to pay for an item they're considering purchasing. We're happy to announce that soon you'll be able to get this kind of information based on activity on eBay's sites with our newest service, eBay Marketplace Research.

eBay Marketplace Research [http://pages.ebay.com/marketplace_research/index.html?ssPageName=CMDV:AB], launching this week, will help you understand overall listing, selling, and searching trends across the eBay site, and give you the information you need to become a more informed buyer or seller.

Some of the features of eBay Marketplace Research include:

-the ability to analyze key information like the average sale prices, average start prices, and average Buy It Now prices of items
-the ability to explore the top keyword searches on eBay by category and by related keywords
charts to help you see buying and selling trends in the eBay marketplace
-access to completed items data going back up to 90 days

eBay Marketplace Research is a subscription-based service, offered in three levels -- Fast Pass, Basic, and Pro. Choose the level that best meets your research needs on eBay.

To learn more, please visit the eBay Marketplace Research page [http://pages.ebay.com/marketplace_research/index.html?ssPageName=CMDV:AB]. I hope you can also join the Product Marketing team for an online workshop on eBay Marketplace Research [http://forums.ebay.com/db2/thread.jspa?threadID=1000119181&ssPageName=CMDV:AB], scheduled for November 17th at 11:00 am PT. We've also created a new discussion board for eBay Marketplace Research for you to share your thoughts on this new service.
http://forums.ebay.com/db1/forum.jspa?forumID=1000000020&ssPageName=CMDV:AB

Sincerely,
John Bodine,
Product Marketing Manager