A nifty little tool for checking pricing of items on ebay:

Get4It is a free service for researching selling price information including highest, lowest, and common prices. Plus, every search includes price graphs and statistics to let you quickly see exactly what you are looking or.

Its not Terapeak, but it doesn’t cost a subscription fee either. If you are starting out, or maybe considering a new product type you could find out a bit more information on the success rate.

Things to note:

Is the marketplace flooded?
Can you compete with quality and/or price?
Is there enough margin left after sale to cover fees?
What is the sell though rate?
Can you compete on shipping?