Neat site, thanks for sharing. Here's some constructive feedback for you.

* Filter results by eBay category.

* Outlier elimination such as excluding "broken" items (e.g. listings containing commonly used words such as "spares or repair", "cracked screen", "damaged").

* Country specific currency (e.g. for UK searches show the results in GBP, £).

* Predict a fair market value for a given search. Useful when trying to sell items second hand as an "arm's-length transaction".